CVE-2025-21846

Summary

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.

Affected Software

VendorProductVersion RangeStatus
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 8acbf4a88c6a98c8ed00afd1a7d1abcca9b4735eaffected
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < b03782ae707cc45e65242c7cddd8e28f1c22cde5affected
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 5d5b936cfa4b0d5670ca7420ef165a074bc008ebaffected
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 5ee8da9bea70dda492d61f075658939af33d8410affected
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 5c928e14a2ccd99462f2351ead627b58075bb736affected
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 5a59ced8ffc71973d42c82484a719c8f6ac8f7f7affected
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < a8136afca090412a36429cb6c2543c714d9c0f84affected
LinuxLinux1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 56d5f3eba3f5de0efdd556de4ef381e109b973a9affected
LinuxLinux2.6.12affected
LinuxLinux0 < 2.6.12unaffected
LinuxLinux5.4.291 <= 5.4.*unaffected
LinuxLinux5.10.235 <= 5.10.*unaffected
LinuxLinux5.15.179 <= 5.15.*unaffected
LinuxLinux6.1.130 <= 6.1.*unaffected
LinuxLinux6.6.80 <= 6.6.*unaffected
LinuxLinux6.12.17 <= 6.12.*unaffected
LinuxLinux6.13.5 <= 6.13.*unaffected
LinuxLinux6.14 <= *unaffected

Weaknesses

ADP Enrichment

CISA ADP Vulnrichment

  • SSVC:
  • Exploitation: none
    • Automatable: no
    • Technical Impact: partial

CVE Program Container

Additional References

Additional References

References