{ "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-2026-100839", "tracking": { "current_release_date": "2026-09-30T15:41:07.857711Z", "generator": { "date": "2026-02-17T15:00:00Z", "engine": { "name": "V.E.L.M.A", "version": "1.7" } }, "id": "CVE-2026-100839", "initial_release_date": "2026-09-27T02:25:44.483338Z", "revision_history": [ { "date": "2026-09-27T02:25:44.483338Z", "number": "1", "summary": "CVE created.| Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| References created (2).| CWES updated (1)." }, { "date": "2026-09-27T02:25:46.020950Z", "number": "2", "summary": "NCSC Score created." }, { "date": "2026-09-27T04:27:19.106694Z", "number": "3", "summary": "NCSC Score updated." }, { "date": "2026-09-27T07:35:09.329068Z", "number": "4", "summary": "NCSC Score updated." }, { "date": "2026-09-27T12:10:58.931002Z", "number": "5", "summary": "Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| References created (4).| CWES updated (1)." }, { "date": "2026-09-27T12:11:09.000969Z", "number": "6", "summary": "NCSC Score updated." }, { "date": "2026-09-27T15:15:09.515774Z", "number": "7", "summary": "EPSS created.| Unknown change." }, { "date": "2026-09-27T18:13:02.379323Z", "number": "8", "summary": "Source created.| CVE status created. (valid)| Description created for source.| CVSS created.| Products created (1).| References created (3).| CWES updated (1)." }, { "date": "2026-09-27T18:13:03.320788Z", "number": "9", "summary": "Source created.| CVE status created. (valid)| Description created for source.| References created (3)." }, { "date": "2026-09-27T18:13:10.010773Z", "number": "10", "summary": "NCSC Score updated." }, { "date": "2026-09-28T12:42:08.623454Z", "number": "11", "summary": "CVSS created.| CWES created (1).| Products created (2).| References created (2).| Description created for source.| Unknown change." }, { "date": "2026-09-28T12:42:11.436190Z", "number": "12", "summary": "NCSC Score updated." }, { "date": "2026-09-29T16:13:19.457060Z", "number": "13", "summary": "EPSS created.| Unknown change." }, { "date": "2026-09-29T18:31:24.441087Z", "number": "14", "summary": "NCSC Score updated." }, { "date": "2026-09-30T15:41:05.281917Z", "number": "15", "summary": "Unknown change." } ], "status": "interim", "version": "15" } }, "product_tree": { "branches": [ { "branches": [ { "branches": [ { "category": "product_version_range", "name": "vers:semver/1.18.0", "product": { "name": "vers:semver/1.18.0", "product_id": "CSAFPID-9478899" } }, { "category": "product_version_range", "name": "vers:semver/<1.18.0", "product": { "name": "vers:semver/<1.18.0", "product_id": "CSAFPID-9478900" } }, { "category": "product_version_range", "name": "vers:unknown/>=0|<1.18.0", "product": { "name": "vers:unknown/>=0|<1.18.0", "product_id": "CSAFPID-9475358" } } ], "category": "product_name", "name": "contrast" } ], "category": "vendor", "name": "edgelesssys" } ] }, "vulnerabilities": [ { "cve": "CVE-2026-100839", "cwe": { "id": "CWE-94", "name": "Improper Control of Generation of Code ('Code Injection')" }, "notes": [ { "category": "description", "text": "Contrast is a confidential-computing runtime for Kubernetes. In versions before 1.18.0, the guest kernel's ACPI/AML handling is vulnerable to an AML injection attack (\"BadAML\"). ACPI tables containing AML bytecode are passed from the untrusted host (QEMU) to the guest firmware (OVMF) and on to the Linux kernel, whose AML interpreter executes them. An attacker controlling the host — an assumed adversary in Contrast's threat model — can craft a table with malicious, Turing-complete AML bytecode that the guest kernel interprets with access to the full guest memory, including private pages, resulting in arbitrary code execution and disclosure or modification of confidential guest data. The issue affects the AMD SEV-SNP platforms Metal-QEMU-SNP and Metal-QEMU-SNP-GPU; Metal-QEMU-TDX is not affected because ACPI table contents are measured into RTMR 0 by OVMF on Intel TDX. Version v1.18.0 mitigates the attack by sandboxing the kernel AML interpreter so that it cannot read or write private memory pages. This weakness is not specific to Contrast but is generic to Confidential Computing setups that expose the ACPI interface to the host.", "title": "cveprojectv5 - https://www.cve.org/CVERecord?id=CVE-2026-100839" }, { "category": "description", "text": "Contrast is a confidential-computing runtime for Kubernetes. In versions before 1.18.0, the guest kernel's ACPI/AML handling is vulnerable to an AML injection attack (\"BadAML\"). ACPI tables containing AML bytecode are passed from the untrusted host (QEMU) to the guest firmware (OVMF) and on to the Linux kernel, whose AML interpreter executes them. An attacker controlling the host — an assumed adversary in Contrast's threat model — can craft a table with malicious, Turing-complete AML bytecode that the guest kernel interprets with access to the full guest memory, including private pages, resulting in arbitrary code execution and disclosure or modification of confidential guest data. The issue affects the AMD SEV-SNP platforms Metal-QEMU-SNP and Metal-QEMU-SNP-GPU; Metal-QEMU-TDX is not affected because ACPI table contents are measured into RTMR 0 by OVMF on Intel TDX. Version v1.18.0 mitigates the attack by sandboxing the kernel AML interpreter so that it cannot read or write private memory pages. This weakness is not specific to Contrast but is generic to Confidential Computing setups that expose the ACPI interface to the host.", "title": "nvd - https://nvd.nist.gov/vuln/detail/CVE-2026-100839" }, { "category": "description", "text": "Contrast is a confidential-computing runtime for Kubernetes. In versions before 1.18.0, the guest kernel's ACPI/AML handling is vulnerable to an AML injection attack (\"BadAML\"). ACPI tables containing AML bytecode are passed from the untrusted host (QEMU) to the guest firmware (OVMF) and on to the Linux kernel, whose AML interpreter executes them. An attacker controlling the host — an assumed adversary in Contrast's threat model — can craft a table with malicious, Turing-complete AML bytecode that the guest kernel interprets with access to the full guest memory, including private pages, resulting in arbitrary code execution and disclosure or modification of confidential guest data. The issue affects the AMD SEV-SNP platforms Metal-QEMU-SNP and Metal-QEMU-SNP-GPU; Metal-QEMU-TDX is not affected because ACPI table contents are measured into RTMR 0 by OVMF on Intel TDX. Version v1.18.0 mitigates the attack by sandboxing the kernel AML interpreter so that it cannot read or write private memory pages. This weakness is not specific to Contrast but is generic to Confidential Computing setups that expose the ACPI interface to the host.", "title": "osv - https://www.googleapis.com/download/storage/v1/b/osv-vulnerabilities/o/GIT%2FCVE-2026-100839.json?alt=media" }, { "category": "description", "text": "# BadAML\n\nBadAML is an AML injection attack that exploits the ACPI interface and allows arbitrary code execution in a confidential VM. The attack was first published in 2024:\n\n- \n- \n\n## Impact\n\nAn attacker with control over the host (which is assumed in the attacker model of Contrast) can execute malicious AML code to gain arbitrary code execution within the confidential guest.\n\nAML is byte code embedded in ACPI tables that are passed from the host (QEMU) to the guest firmware (OVMF), and then passed from OVMF to the Linux kernel. The Linux kernel has an interpreter that executes the AML code. An attacker can craft a table with malicious AML code and the kernel will execute it. AML is Turing-complete and the interpreter has access to the full guest memory, including private pages.\n\nSee the [paper](https://dl.acm.org/doi/pdf/10.1145/3719027.3765123) for a detailed description and background of the attack.\n\nNote that this is not a vulnerability specific to Contrast, but rather a generic vulnerability in Confidential Computing setups that use the ACPI interface.\n\n## Affected platforms\n\nThis issue affects the SNP platforms supported by Contrast: `Metal-QEMU-SNP` and `Metal-QEMU-SNP-GPU`.\nUsers on these platforms should switch to the fixed Contrast version immediately.\n\n`Metal-QEMU-TDX` isn't affected, as the content of the ACPI tables is covered by the runtime measurements (measured into RTMR 0 by OVMF) on Intel TDX.\n\n## Patches\n\nA sandbox similar to the one proposed in the paper has been implemented in the Linux kernel used by Contrast. The sandbox denies access to private memory pages by doing a page table lookup on every read/write by the AML interpreter.\n\nThis mitigates the attack completely: While an attacker can still run AML code, the code cannot read or modify private memory pages. Shared pages are readable/writable by the host hypervisor anyway.", "title": "osv - https://www.googleapis.com/download/storage/v1/b/osv-vulnerabilities/o/Go%2FGHSA-g9ww-x58f-9g6m.json?alt=media" }, { "category": "description", "text": "Contrast BadAML injection allows arbitrary code execution in github.com/edgelesssys/contrast", "title": "osv - https://www.googleapis.com/download/storage/v1/b/osv-vulnerabilities/o/Go%2FGO-2026-4863.json?alt=media" }, { "category": "other", "text": "0.00149", "title": "EPSS" }, { "category": "other", "text": "CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X", "title": "CVSSV4" }, { "category": "other", "text": "8.4", "title": "CVSSV4 base score" }, { "category": "other", "text": "4.3", "title": "NCSC Score" }, { "category": "other", "text": "There is cwe data available from source Nvd, The value of the most recent CVSS (V3) score", "title": "NCSC Score top decreasing factors" } ], "product_status": { "known_affected": [ "CSAFPID-9475358", "CSAFPID-9478900" ], "known_not_affected": [ "CSAFPID-9478899" ] }, "references": [ { "category": "external", "summary": "Source - osv", "url": "https://www.googleapis.com/download/storage/v1/b/osv-vulnerabilities/o/Go%2FGHSA-g9ww-x58f-9g6m.json?alt=media" }, { "category": "external", "summary": "Source - osv", "url": "https://www.googleapis.com/download/storage/v1/b/osv-vulnerabilities/o/Go%2FGO-2026-4863.json?alt=media" }, { "category": "external", "summary": "Source - nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-100839" }, { "category": "external", "summary": "Source - ncscclear", "url": "https://vulnerabilities.ncsc.nl/manual/CVE-2026-100839" }, { "category": "external", "summary": "Source - osv", "url": "https://www.googleapis.com/download/storage/v1/b/osv-vulnerabilities/o/GIT%2FCVE-2026-100839.json?alt=media" }, { "category": "external", "summary": "Source - first", "url": "https://api.first.org/data/v1/epss" }, { "category": "external", "summary": "Source - cveprojectv5", "url": "https://www.cve.org/CVERecord?id=CVE-2026-100839" }, { "category": "external", "summary": "Reference - cveprojectv5; nvd; osv", "url": "https://github.com/edgelesssys/contrast/security/advisories/GHSA-g9ww-x58f-9g6m" }, { "category": "external", "summary": "Reference - cveprojectv5; nvd; osv", "url": "https://www.vulncheck.com/advisories/contrast-before-1.18.0-aml-injection-remote-code-execution" }, { "category": "external", "summary": "Reference - osv", "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/100xxx/CVE-2026-100839.json" }, { "category": "external", "summary": "Reference - osv", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-100839" }, { "category": "external", "summary": "Reference - osv", "url": "https://blackhat.com/eu-24/briefings/schedule/#aml-injection-attacks-on-confidential-vms-42723" }, { "category": "external", "summary": "Reference - osv", "url": "https://dl.acm.org/doi/pdf/10.1145/3719027.3765123" } ], "scores": [ { "cvss_v3": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N", "baseScore": 8.4, "baseSeverity": "HIGH" }, "products": [ "CSAFPID-9475358", "CSAFPID-9478900" ] } ], "title": "CVE-2026-100839" } ] }