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VulnerabilityPublished Updated

CVE-2026-72338: Linux kernel · net/sched: act_pedit: fix TOCTOU heap OOB write in tc offload

Affects Linux kernelSource CVE Database V5

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Not known to be exploited · CVSS 7.8 High · fixed in 27488e1a7f19757e6146edca9458ed4ffc545557 : patch Linux kernel soon.

Data as of 30 Oct 2026, 12:49 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CNA (Linux)CVSS 3.17.8
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact
Total control over the software or total information disclosure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in 27488e1a7f19757e6146edca9458ed4ffc545557, 8e49cd891bda447c68122d672510a604a8bb6b24, 8b519cbcabe836a441369fbec1a8a6518a709251 +3
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 15 Aug 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ 71d0ed7079dffbc5cd0941d77d9b84e04109c9bb, < 27488e1a7f19757e6146edca9458ed4ffc545557
Fixed in
  • 27488e1a7f19757e6146edca9458ed4ffc545557
LinuxLinuxAffected
  • ≥ 71d0ed7079dffbc5cd0941d77d9b84e04109c9bb, < 8e49cd891bda447c68122d672510a604a8bb6b24
Fixed in
  • 8e49cd891bda447c68122d672510a604a8bb6b24
LinuxLinuxAffected
  • ≥ 71d0ed7079dffbc5cd0941d77d9b84e04109c9bb, < 8b519cbcabe836a441369fbec1a8a6518a709251
Fixed in
  • 8b519cbcabe836a441369fbec1a8a6518a709251
LinuxLinuxAffected
  • ≥ 71d0ed7079dffbc5cd0941d77d9b84e04109c9bb, < 6f9b23eb92a894ae1118893996943990ee0b860e
Fixed in
  • 6f9b23eb92a894ae1118893996943990ee0b860e
LinuxLinuxAffected
  • ≥ 71d0ed7079dffbc5cd0941d77d9b84e04109c9bb, < 1afdf2268b71251ea70d80bd8232a2f022e62a73
Fixed in
  • 1afdf2268b71251ea70d80bd8232a2f022e62a73
LinuxLinuxAffected
  • ≥ 71d0ed7079dffbc5cd0941d77d9b84e04109c9bb, < 0d8532a5e972a5351cf4ee4a435e0d65cbba8f23
Fixed in
  • 0d8532a5e972a5351cf4ee4a435e0d65cbba8f23

Description

In 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. zdi-disclosures@trendmicro.com 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.

References

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