Linux Kernel up to 7.2-rc2 act_pedit net/sched/act_pedit.c tcf_pedit_offload_act_setup tcfp_nkeys toctou

CVSS Meta Temp Score
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CTI Interest Score
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7.8$0-$5k0.94+

Summaryinfo

A vulnerability marked as very critical has been reported in Linux Kernel up to 6.6.144/6.12.96/6.18.39/7.1.4/7.2-rc2. This affects the function tcf_pedit_offload_act_setup of the file net/sched/act_pedit.c of the component act_pedit. The manipulation of the argument tcfp_nkeys leads to toctou. This vulnerability is referenced as CVE-2026-72338. The attack can only be performed from a local environment. No exploit is available.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.6.144/6.12.96/6.18.39/7.1.4/7.2-rc2 and classified as very critical. This issue affects the function tcf_pedit_offload_act_setup of the file net/sched/act_pedit.c of the component act_pedit. The manipulation of the argument tcfp_nkeys with an unknown input leads to a toctou vulnerability. Using CWE to declare the problem leads to CWE-367. The product checks the state of a resource before using that resource, but the resource's state can change between the check and the use in a way that invalidates the results of the check. This can cause the product to perform invalid actions when the resource is in an unexpected state. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

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. [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.

It is possible to read the advisory at git.kernel.org. The identification of this vulnerability is CVE-2026-72338 since 08/09/2026. The exploitation is known to be easy. Attacking locally is a requirement. The exploitation requires an enhanced level of successful authentication. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 08/15/2026).

Upgrading to version 6.6.145, 6.12.97, 6.18.40, 7.1.5 or 7.2-rc3 eliminates this vulnerability. Applying the patch 0d8532a5e972a5351cf4ee4a435e0d65cbba8f23/27488e1a7f19757e6146edca9458ed4ffc545557/6f9b23eb92a894ae1118893996943990ee0b860e/8e49cd891bda447c68122d672510a604a8bb6b24/8b519cbcabe836a441369fbec1a8a6518a709251 is able to eliminate this problem.

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Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 8.2
VulDB Meta Temp Score: 7.8

VulDB Base Score: 8.2
VulDB Temp Score: 7.8
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Toctou
CWE: CWE-367 / CWE-362
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: No

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.6.145/6.12.97/6.18.40/7.1.5/7.2-rc3
Patch: 0d8532a5e972a5351cf4ee4a435e0d65cbba8f23/27488e1a7f19757e6146edca9458ed4ffc545557/6f9b23eb92a894ae1118893996943990ee0b860e/8e49cd891bda447c68122d672510a604a8bb6b24/8b519cbcabe836a441369fbec1a8a6518a709251

Timelineinfo

08/09/2026 CVE reserved
08/15/2026 +6 days Advisory disclosed
08/15/2026 +0 days VulDB entry created
08/15/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-72338 (🔒)
GCVE (CVE): GCVE-0-2026-72338
GCVE (VulDB): GCVE-100-390695

Entryinfo

Created: 08/15/2026 14:06
Changes: 08/15/2026 14:06 (61)
Complete: 🔍
Cache ID: 216::103

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