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CVE Record

CVE-2026-31554: futex: Require sys_futex_requeue() to have identical flags

In the Linux kernel, the following vulnerability has been resolved: futex: Require sys_futex_requeue() to have identical flags Nicholas reported that his LLM found it was possible to create a UaF when sys_futex_requeue() is used with different flags. The initial motivation for allowing different flags was the variable sized futex, but since that hasn't been merged (yet), simply mandate the flags are identical, as is the case for the old style sys_futex() requeue operations.

HighCVSS 7.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

A Linux kernel flaw can let a low-privileged local user trigger a use-after-free condition through inconsistent futex requeue flags. Successful exploitation could compromise confidentiality, integrity, and availability. It is not remotely exploitable under the supplied CVSS assessment, and the sources provide no evidence of active exploitation.

Executive priority

Treat this as a high-priority kernel maintenance issue, especially on shared, multi-user, or workload-hosting infrastructure. Patch promptly through supported distribution channels. Emergency internet-edge remediation is not indicated by the supplied evidence because exploitation requires local access and active exploitation is not documented.

Technical view

The newer sys_futex_requeue() path allowed source and destination futex operations to use different flags. That mismatch could create a use-after-free condition. The stable kernel correction requires both flags to be identical, matching the invariant already enforced by older sys_futex() requeue operations.

Likely exposure

Exposure requires an affected Linux kernel and low-privileged local code execution. Multi-user and workload-hosting systems therefore deserve particular attention. The supplied version entries do not form an unambiguous affected range, so validate each distribution kernel through vendor build information or presence of a referenced fix.

Exploitation context

CVSS 3.1 scores this 7.8 with local access, low privileges, low complexity, and no user interaction. CISA KEV status is false, and the supplied sources do not document active exploitation, public exploit availability, or remote reachability.

Researcher notes

The source describes a use-after-free caused by differing futex requeue flags and fixes the invariant directly. No CWE is assigned. Precise vulnerable version boundaries, exploitation reliability, and affected distribution packages are not established by the supplied bundle.

Mitigation direction

  • Install a distribution or vendor kernel containing the CVE-2026-31554 fix or an equivalent backport.
  • Reboot affected systems after updating so the corrected kernel is running.
  • Prioritize systems allowing untrusted or low-privileged local code execution.
  • If no corrected package is available, obtain interim risk-reduction guidance from the kernel distributor.

Validation and detection

  • Inventory active kernel builds and map them against distribution advisories for CVE-2026-31554.
  • Verify the running kernel incorporates a cited stable commit or documented vendor backport.
  • Confirm the active kernel version after reboot, not merely the installed package version.
  • Identify affected hosts where untrusted users or workloads can execute local code.
Prepared
Confidence
medium
Sources
6

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

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.

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CVE-2026-31554 mapping review

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Vulnerability profileCVE Program record
Severity
High
CVSS
7.8 (3.1)
Known Exploited
No
Published

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

Official CVE source material

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.

1CVSS vectors
3Timeline events
0ADP providers
5Source links

CVSS vector scores

1 official score

We 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.

ScoreVersionSeverityVectorExploitImpactSource
7.8CVSS 3.1HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H1.85.9Linux

Vulnerability scoring details

Base CVSS 3.1 score

7.8High
CVSS 3.1 vector shape for CVE-2026-31554Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinux0f4b5f972216782a4acb1ae00dcb55173847c2ff, 0f4b5f972216782a4acb1ae00dcb55173847c2ff, 0f4b5f972216782a4acb1ae00dcb55173847c2ff, 0f4b5f972216782a4acb1ae00dcb55173847c2ffunaffected
LinuxLinux6.7, 0, 6.12.80, 6.18.21, 6.19.11, 7.0affected
Weakness

CWE details

No CWE listed

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