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CVE-2026-46302 Linux CVE debrief

A vulnerability in the Linux kernel has been resolved, specifically in the SELinux (Security-Enhanced Linux) subsystem. The issue was related to the /sys/fs/selinux/policy file, which previously could only be opened once at any given time. This limitation allowed any process to block other processes from reading the kernel policy, potentially causing inconsistencies or denial of service. The original motivation for this limitation was to prevent an inconsistent view of the policy size and to prevent userspace from allocating kernel memory without bound. However, this approach is now considered problematic. The fix involves eliminating the policy_opened flag and reducing the critical section where the policy mutex is held. Additionally, a couple of extraneous BUG_ONs were dropped as part of the changes.

Vendor
Linux
Product
Unknown
CVSS
MEDIUM 5.5
CISA KEV
Not listed in stored evidence
Original CVE published
2026-06-08
Original CVE updated
2026-07-23
Advisory published
2026-06-08
Advisory updated
2026-07-23

Who should care

System administrators and users of Linux systems should be aware of this vulnerability and the subsequent fix. Although the vulnerability has been resolved, understanding the nature of the issue can help in assessing the risk and ensuring that systems are up-to-date with the latest security patches.

Technical summary

The Linux kernel vulnerability, identified as CVE-2026-46302, relates to the SELinux subsystem's handling of the /sys/fs/selinux/policy file. Previously, only a single process could open this file at any time, potentially allowing a process to block others from accessing the kernel policy. The fix removes the policy_opened flag and shrinks the critical section held by the policy mutex, addressing the issue while also removing unnecessary BUG_ON statements.

Defensive priority

Medium

Recommended defensive actions

  • Ensure that Linux systems are updated with the latest kernel patches.
  • Review system configurations and SELinux policies to ensure they are secure and up-to-date.

Evidence notes

The CVE-2026-46302 vulnerability has been resolved in the Linux kernel. The fix allows for multiple opens of /sys/fs/selinux/policy, addressing a potential denial-of-service issue and improving security.

Sources and references

Verified primary and authoritative sources

  • CVE-2026-46302 CVE Program record

    Publisher, destination, and source semantics verified

    URL: https://www.cve.org/CVERecord?id=CVE-2026-46302

    CVE Program - Official CVE Program record with source-provided CVE metadata.

  • CVE-2026-46302 NVD vulnerability detail

    Publisher, destination, and source semantics verified

    URL: https://nvd.nist.gov/vuln/detail/CVE-2026-46302

    NIST National Vulnerability Database - Official NIST NVD detail page and source-specific vulnerability assessment.

Supplemental references

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/714362f3779dfa453a78ced32396a72726962a41

    416baaa9-dc9f-4396-8d5f-8c081fb06d67

  • Source reference

    Unverified legacy reference

    URL: https://git.kernel.org/stable/c/a02cd6805562305f936e807da83e253b719dd965

    416baaa9-dc9f-4396-8d5f-8c081fb06d67

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.