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CVE Record

CVE-2026-31673: af_unix: read UNIX_DIAG_VFS data under unix_state_lock

In the Linux kernel, the following vulnerability has been resolved: af_unix: read UNIX_DIAG_VFS data under unix_state_lock Exact UNIX diag lookups hold a reference to the socket, but not to u->path. Meanwhile, unix_release_sock() clears u->path under unix_state_lock() and drops the path reference after unlocking. Read the inode and device numbers for UNIX_DIAG_VFS while holding unix_state_lock(), then emit the netlink attribute after dropping the lock. This keeps the VFS data stable while the reply is being built.

HighCVSS 7.8Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

A local, low-privileged Linux user may trigger a race while the kernel reports UNIX socket filesystem information. The kernel can read path data while another operation releases it, potentially compromising confidentiality, integrity, or availability. Network-only attackers are not indicated by the supplied CVSS vector.

Executive priority

Prioritize timely remediation on shared, multi-user, and untrusted-workload Linux hosts. Treat this as high severity but not an internet-routable emergency based on current evidence. Routine single-user systems can follow risk-based kernel maintenance after exposure is verified.

Technical view

Exact UNIX socket diagnostic lookups retain the socket but not its path. Concurrent socket release clears and later drops that path reference. The fix reads inode and device values while holding unix_state_lock, then emits the netlink attribute after unlocking, keeping UNIX_DIAG_VFS data stable.

Likely exposure

Exposure requires an affected Linux kernel and local low-privileged access. Multi-user systems and hosts running untrusted workloads deserve particular attention. The supplied affected-version data is ambiguous, including unusual and duplicated entries, so determine exposure through distribution advisories and fix-commit inclusion rather than version strings alone.

Exploitation context

The CVSS 3.1 score is 7.8 with local access, low complexity, low privileges, and no user interaction. The record is not marked as CISA KEV, and the supplied sources provide no evidence of active exploitation or a public exploit. Exploitability beyond the stated vector remains unconfirmed.

Researcher notes

The flaw is a synchronization and lifetime issue around u->path during UNIX_DIAG_VFS reply construction. The correction snapshots inode and device numbers under unix_state_lock. The source bundle does not identify a CWE, crash signature, proof of concept, exploitation telemetry, or vendor-specific package boundaries.

Mitigation direction

  • Install a vendor-supported kernel containing the applicable stable fix commit.
  • Reboot into the updated kernel after installation.
  • If patching is delayed, reduce untrusted local access where operationally feasible.
  • Check distribution guidance for branch-specific packages and compensating controls.

Validation and detection

  • Inventory running kernel versions across Linux systems.
  • Map each kernel package to its distribution security advisory.
  • Confirm the running kernel contains the applicable stable fix.
  • Verify systems rebooted into the corrected kernel, not merely installed it.
  • Monitor vendor advisories for clarified affected ranges or exploitation evidence.
Prepared
Confidence
medium
Sources
10

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-2026-31673 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
9Source 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-2026-31673Attack 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
LinuxLinux5f7b0569460b7d8d01ca776430a00505a68b7584, 5f7b0569460b7d8d01ca776430a00505a68b7584, 5f7b0569460b7d8d01ca776430a00505a68b7584, 5f7b0569460b7d8d01ca776430a00505a68b7584, 5f7b0569460b7d8d01ca776430a00505a68b7584, 5f7b0569460b7d8d01ca776430a00505a68b7584, 5f7b0569460b7d8d01ca776430a00505a68b7584, 5f7b0569460b7d8d01ca776430a00505a68b7584unaffected
LinuxLinux3.3, 0, 5.10.258, 5.15.209, 6.1.175, 6.6.136, 6.12.83, 6.18.24, 6.19.14, 7.0affected
Weakness

CWE details

No CWE listed

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