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Findings

CVE-2025-21846

In the Linux kernel, the following vulnerability has been resolved: acct: perform last write from workqueue In [1] it was reported that the acct(2) system call can be…

Published Mar 12, 2025 · updated Oct 15, 2026 · linux linux kernel

In the Linux kernel, the following vulnerability has been resolved: acct: perform last write from workqueue In [1] it was reported that the acct(2) system call can be used to trigger NULL deref in cases where it is set to write to a file that triggers an internal lookup. This can e.g., happen when pointing acc(2) to /sys/power/resume. At the point the where the write to this file happens the calling task has already exited and called exit_fs(). A lookup will thus trigger a NULL-deref when accessing current->fs. Reorganize the code so that the the final write happens from the workqueue but with the caller's credentials. This preserves the (strange) permission model and has almost no regression risk. This api should stop to exist though.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Mar 12, 2025 · NIST NVD

    Detected

    In the Linux kernel, the following vulnerability has been resolved: acct: perform last write from workqueue In [1] it was reported that the acct(2) system call can be used to trigger NULL deref in cases where it is set to write to a file that triggers an internal lookup. This can e.g., happen when pointing acc(2) to /sys/power/resume. At the point the where the write to this file happens the calli

  2. Oct 15, 2026 · NIST NVD

    Updated

    In the Linux kernel, the following vulnerability has been resolved: acct: perform last write from workqueue In [1] it was reported that the acct(2) system call can be used to trigger NULL deref in cases where it is set to write to a file that triggers an internal lookup. This can e.g., happen when pointing acc(2) to /sys/power/resume. At the point the where the write to this file happens the calli

Affected

  • cpe linux/linux kernelversion unspecified
  • cpe linux/linux kernel6.14

Sources

  • CVE.orgVulnerability recordCVE-2025-21846

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2025-21846

    30-day exploitation probability 0.3%

    first.org
  • NIST NVDVulnerability recordCVE-2025-21846

    In the Linux kernel, the following vulnerability has been resolved: acct: perform last write from workqueue In [1] it was reported that the acct(2) system call can be used to trigger NULL deref in cases where it is set to write to a file that triggers an internal lookup. This c

    nvd.nist.gov

References

CVE-2025-21846 · ZeroDay Findings