Vulnerability-Lookup

UBUNTU-CVE-2026-43631 (CVE-2026-43631)

Vulnerability from osv_ubuntu – Published: 2026-08-06 22:17 – Updated: 2026-08-13 00:06 – Source website

Details

llama.cpp builds b7492 through the latest b9060 contains a use-after-free vulnerability in the vocab pointer of llama-server when the --sleep-idle-seconds feature is enabled, allowing unauthenticated remote attackers to execute arbitrary code. Attackers can trigger the vulnerability by sending requests to affected endpoints while the server transitions to sleep mode, causing concurrent worker threads to dereference a freed vocab pointer that can be reclaimed with attacker-controlled data to achieve remote code execution.

Severity

8.1 (High)


                    
                      CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

9.2 (Critical)


                    
                      CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

N/A (UNKNOWN)


                    
                      medium

References

URL

Type

	https://ubuntu.com/security/CVE-2026-43631	REPORT
	https://www.cve.org/CVERecord?id=CVE-2026-43631	REPORT
	https://github.com/Vladimir-tokarev-cyera/llama-c…	REPORT

JSON

To clipboard

{
  "affected": [
    {
      "ecosystem_specific": {
        "binaries": [
          {
            "binary_name": "libllama0",
            "binary_version": "8681+dfsg-1"
          },
          {
            "binary_name": "llama.cpp",
            "binary_version": "8681+dfsg-1"
          },
          {
            "binary_name": "llama.cpp-examples",
            "binary_version": "8681+dfsg-1"
          },
          {
            "binary_name": "llama.cpp-tests",
            "binary_version": "8681+dfsg-1"
          },
          {
            "binary_name": "llama.cpp-tools",
            "binary_version": "8681+dfsg-1"
          },
          {
            "binary_name": "llama.cpp-tools-extra",
            "binary_version": "8681+dfsg-1"
          },
          {
            "binary_name": "python3-gguf",
            "binary_version": "8681+dfsg-1"
          }
        ]
      },
      "package": {
        "ecosystem": "Ubuntu:26.04:LTS",
        "name": "llama.cpp",
        "purl": "pkg:deb/ubuntu/llama.cpp@8681+dfsg-1?arch=source\u0026distro=resolute"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ],
      "versions": [
        "5882+dfsg-2",
        "8064+dfsg-1ubuntu1",
        "8681+dfsg-1"
      ]
    }
  ],
  "aliases": [],
  "details": "llama.cpp builds b7492 through the latest b9060 contains a use-after-free vulnerability in the vocab pointer of llama-server when the --sleep-idle-seconds feature is enabled, allowing unauthenticated remote attackers to execute arbitrary code. Attackers can trigger the vulnerability by sending requests to affected endpoints while the server transitions to sleep mode, causing concurrent worker threads to dereference a freed vocab pointer that can be reclaimed with attacker-controlled data to achieve remote code execution.",
  "id": "UBUNTU-CVE-2026-43631",
  "modified": "2026-08-13T00:06:43Z",
  "published": "2026-08-06T22:17:00Z",
  "references": [
    {
      "type": "REPORT",
      "url": "https://ubuntu.com/security/CVE-2026-43631"
    },
    {
      "type": "REPORT",
      "url": "https://www.cve.org/CVERecord?id=CVE-2026-43631"
    },
    {
      "type": "REPORT",
      "url": "https://github.com/Vladimir-tokarev-cyera/llama-cpp-security-patches"
    }
  ],
  "related": [],
  "schema_version": "1.7.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    },
    {
      "score": "CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    },
    {
      "score": "medium",
      "type": "Ubuntu"
    }
  ],
  "upstream": [
    "CVE-2026-43631"
  ]
}

CVE-2026-43631 (GCVE-0-2026-43631)

Vulnerability from cvelistv5 – Published: 2026-08-06 15:52 – Updated: 2026-08-14 16:49 X_Open Source

Title

llama.cpp b7492–b9060 Use-After-Free RCE via llama-server

Summary

Severity

9.2 (Critical)


                        
                          CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

8.1 (High)


                        
                          CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-08-07 13:49 UTC

CWE

CWE-416 - Use After Free
CWE-362 - Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

Assigner

VulnCheck mitre root

References

2 references

URL	Tags
https://github.com/Vladimir-tokarev-cyera/llama-c…	mitigation
https://www.vulncheck.com/advisories/llama-cpp-b7…	third-party-advisory

Impacted products

1 product

Vendor	Product	Version
ggml-org	llama.cpp	Affected: b7492 , ≤ b9060 (custom) cpe:2.3:a:ggml:llama.cpp::::::::

Date Public

2026-05-06 00:00

Credits

Vladimir Tokarev (@G1ND1L4) - Vulnerability Research Tech Lead, Cyera Ofek Itach (@ofekitach) - Security Research Team Lead, Cyera

Show details on NVD website

JSON

To clipboard

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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.