net/sched: act_pedit: fix TOCTOU heap OOB write in tc offload

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-72338
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-15 06:22:07 UTC
Updated2026-08-17 06:18:37 UTC
DescriptionIn the Linux kernel, the following vulnerability has been resolved: net/sched: act_pedit: fix TOCTOU heap OOB write in tc offload There is a TOCTOU race condition in flower lockless approach between sizing a flow_rule buffer and filling it. [email protected] reports: The cls_flower classifier operates with TCF_PROTO_OPS_DOIT_UNLOCKED (fl_change runs without RTNL), while RTM_NEWACTION holds RTNL, so the independent locking domains make the race reachable in practice. KASAN confirms: BUG: KASAN: slab-out-of-bounds in tcf_pedit_offload_act_setup+0x81b/0x930 Write of size 4 at addr ffff888001f27520 by task poc-toctou/312 The buggy address is located 0 bytes to the right of allocated 288-byte region [ffff888001f27400, ffff888001f27520) (cache kmalloc-512) Note: The result is a heap OOB write attacker-controlled content into the adjacent slab object (requires CAP_NET_ADMIN). The fix introduces reading tcfp_nkeys under act->tcfa_lock in all places using a new tcf_pedit_nkeys_locked() which replaces the old tcf_pedit_nkeys(). Additionally we close the remaining TOCTOU window between the sizing read and the fill reads by more careful accounting. Rather than silently truncating the key count, which leads to incorrect action semantics offloaded to hardware and secondary OOB writes if the remaining capacity is zero or consumed by prior actions, we enforce remaining capacity checks and return -ENOSPC if the required space exceeds the remaining capacity.

Risk And Classification

Primary CVSS: v3.1 7.8 HIGH from 416baaa9-dc9f-4396-8d5f-8c081fb06d67

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS: 0.001660000 probability, percentile 0.063370000 (date 2026-08-17)

VersionSourceTypeScoreSeverityVector
3.1416baaa9-dc9f-4396-8d5f-8c081fb06d67Secondary7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
3.1CNADECLARED7.8HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 71d0ed7079dffbc5cd0941d77d9b84e04109c9bb 0d8532a5e972a5351cf4ee4a435e0d65cbba8f23 git Not specified
CNA Linux Linux affected 71d0ed7079dffbc5cd0941d77d9b84e04109c9bb 27488e1a7f19757e6146edca9458ed4ffc545557 git Not specified
CNA Linux Linux affected 71d0ed7079dffbc5cd0941d77d9b84e04109c9bb 6f9b23eb92a894ae1118893996943990ee0b860e git Not specified
CNA Linux Linux affected 71d0ed7079dffbc5cd0941d77d9b84e04109c9bb 8e49cd891bda447c68122d672510a604a8bb6b24 git Not specified
CNA Linux Linux affected 71d0ed7079dffbc5cd0941d77d9b84e04109c9bb 8b519cbcabe836a441369fbec1a8a6518a709251 git Not specified
CNA Linux Linux affected 4.11 Not specified
CNA Linux Linux unaffected 4.11 semver Not specified
CNA Linux Linux unaffected 6.6.145 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.97 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.40 6.18.* semver Not specified
CNA Linux Linux unaffected 7.1.5 7.1.* semver Not specified
CNA Linux Linux unaffected 7.2 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/8b519cbcabe836a441369fbec1a8a6518a709251 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/8e49cd891bda447c68122d672510a604a8bb6b24 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/27488e1a7f19757e6146edca9458ed4ffc545557 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/6f9b23eb92a894ae1118893996943990ee0b860e 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
git.kernel.org/stable/c/0d8532a5e972a5351cf4ee4a435e0d65cbba8f23 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org
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