Security readout for executives and security teams
Plain-English summary
Affected llama-server deployments may let an unauthenticated network attacker take control of the server. The flaw occurs during sleep-mode transitions and can corrupt memory when concurrent workers use released vocabulary data. Compromise could expose model data, alter services, or disrupt availability.
Executive priority
Treat internet-accessible affected servers as an immediate remediation priority. Quickly disable the triggering feature or isolate the service, then establish an authoritative upgrade path. Internal-only deployments still warrant prompt action because successful exploitation could provide full control of the serving process.
Technical view
CVE-2026-43631 is a race condition and use-after-free involving llama-server’s vocab pointer when --sleep-idle-seconds is enabled. Requests arriving during a sleep transition may cause worker threads to dereference freed memory. The supplied description states that attacker-controlled reclamation can lead to remote code execution in builds b7492 through b9060.
Likely exposure
Highest exposure is in network-accessible llama-server instances running builds b7492 through b9060 with --sleep-idle-seconds enabled. Authentication or network controls may reduce reachability, but the described vulnerability itself requires no privileges or user interaction. Instances without that feature enabled are not described as vulnerable.
Exploitation context
The CVSS 4.0 score is 9.2. Exploitation requires network access, a sleep transition, and favorable concurrency or timing conditions. The bundle does not report CISA KEV inclusion or provide evidence of active exploitation. High attack complexity should not be treated as protection for exposed services.
Researcher notes
The reported weakness combines CWE-362 and CWE-416: concurrent activity during sleep transition leaves workers using a freed vocab pointer. CVSS reflects attack requirements through AC:H and AT:P. The bundle’s structured affected entry lists only b7492, while its title and description state b7492 through b9060; confirm exact version boundaries with authoritative guidance.
Mitigation direction
- Disable --sleep-idle-seconds on affected servers as an immediate exposure-reduction measure.
- Restrict llama-server access to trusted networks and authenticated clients.
- Review the cited security-patch repository and vendor guidance before applying a permanent fix.
- Upgrade only to a release explicitly confirmed by authoritative guidance as not affected.
- Restart affected services after configuration or binary changes to clear vulnerable process state.
Validation and detection
- Inventory llama.cpp build identifiers across every llama-server deployment.
- Confirm whether --sleep-idle-seconds is present in startup configuration or service definitions.
- Identify instances reachable from untrusted networks, including through proxies or gateways.
- Review logs for crashes or abnormal behavior around sleep transitions and concurrent requests.
- Verify mitigations in staging, then confirm the deployed build and runtime arguments.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-362: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCWE-416: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2026-43631 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Critical
- CVSS
- 9.2 (4.0)
- Known Exploited
- No
- Published
Vector: 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
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
SSVC decision data
CVSS vector scores
2 official scoresWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest 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——VulnCheckCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H2.25.9VulnCheckVulnerability scoring details
Base CVSS 4.0 score
9.2CriticalVector: 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
Base CVSS 3.1 score
8.1HighVector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/Vladimir-tokarev-cyera/llama-cpp-security-patchesCVE reference, VulnCheck · mitigation
- https://www.vulncheck.com/advisories/llama-cpp-b7492-b9060-use-after-free-rce-via-llama-serverCVE reference, VulnCheck · third-party-advisory
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.
Use After Free
Use After Free represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.