Riskcovery

CVE-2026-64027

net: shaper: rework the VALID marking (again)

State
Published
Severity
7.8 High
Published
Jul 19, 2026
Updated
Oct 19, 2026
Reserved
Jul 19, 2026

Read the record on cve.org

Description

In the Linux kernel, the following vulnerability has been resolved:

net: shaper: rework the VALID marking (again)

Recent commit changed the semantics from NOT_VALID to VALID. I didn't realize that the flags are not stored atomically with the entry in XArray. There's still a race of reader observing a VALID mark for a slot, getting interrupted, writer replacing the entry with a different one, reader continuing, fetching the entry which is now a different pointer than the pointer for which VALID was meant.

The biggest consequence of this is that we may see a UAF since net_shaper_rollback() assumed that entries without VALID can be freed without observing RCU.

Looks like the XArray marks are buying us nothing at this point. Let's convert the code to an explicit valid field. The smp_load_acquire() / smp_store_release() barriers are marginally cleaner.

Scores

CVSSScoreVectorSource
3.17.8 HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:HLinux

Weaknesses

  • CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

Affected Products

ProductVersions
LinuxLinux
  • 93954b40f6a4fc43226c01a15b02732f884500f1 to before 2417df5e7bb4184b9d3a2988036bf2c46e594545Affected
  • 93954b40f6a4fc43226c01a15b02732f884500f1 to before 96ea960dd40fd55302e0fd755176f26a95e6a50cAffected
  • 93954b40f6a4fc43226c01a15b02732f884500f1 to before b8d7519352ba8c6df83259295d4a3bad093cae90Affected
LinuxLinux
  • 6.13Affected
  • before 6.13Not affected
  • 6.18.34 through 6.18.*Not affected
  • 7.0.11 through 7.0.*Not affected
  • 7.1 and laterNot affected

References

Every record here comes from the CVE Program’s CVE List. © 1999–2026 The MITRE Corporation. CVE is a registered trademark of The MITRE Corporation. The records are reproduced under the CVE Program terms of use.