Linux Kernel up to 7.2-rc1 sch_teql net/sched teql_master_xmit slaves use after free

CVSS Meta Temp Score
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CTI Interest Score
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9.5$5k-$25k0.96

Summaryinfo

A vulnerability categorized as very critical has been discovered in Linux Kernel up to 7.2-rc1. This affects the function teql_master_xmit of the file net/sched of the component sch_teql. Executing a manipulation of the argument slaves can lead to use after free. This vulnerability is handled as CVE-2026-72390. The attack can be executed remotely. There is not any exploit available.

Detailsinfo

A vulnerability was found in Linux Kernel up to 7.2-rc1. It has been declared as very critical. This vulnerability affects the function teql_master_xmit of the file net/sched of the component sch_teql. The manipulation of the argument slaves with an unknown input leads to a use after free vulnerability. The CWE definition for the vulnerability is CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. As an impact it is known to affect confidentiality, integrity, and availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: net/sched: sch_teql: Introduce slaves_lock to avoid race condition and UAF The teql master->slaves singly linked list is not protected against multiple writes. It can be mod'ed concurently from teql_master_xmit(), teql_dequeue(), teql_init() and teql_destroy() without holding any list lock or RCU protection. [email protected] has demonstrated that the qdisc is freed after an RCU grace period, but teql_master_xmit() running on another CPU can still hold a stale pointer into the list, resulting in a slab-use-after-free: BUG: KASAN: slab-use-after-free in teql_master_xmit+0xf0f/0x16b0 Read of size 8 at addr ffff888013fb0440 by task poc/332 Freed 512-byte region [ffff888013fb0400, ffff888013fb0600) (kmalloc-512) The fix? Add a per-master slaves_lock spinlock that serializes all mutations of master->slaves and the NEXT_SLAVE() links in teql_destroy() and teql_qdisc_init(). teql_master_xmit() also takes the same slaves_lock around those updates. Annotate master->slaves and the per-slave ->next pointer with __rcu and use the appropriate RCU accessors everywhere they are touched: rcu_assign_pointer() on the writer side (under slaves_lock), rcu_dereference_protected() for the writer-side loads (also under slaves_lock), rcu_dereference_bh() for the loads in teql_master_xmit() and rtnl_dereference() for the loads in teql_master_open()/teql_master_mtu(), which run under RTNL. Pair this with rcu_read_lock_bh()/rcu_read_unlock_bh() around the list traversal in teql_master_xmit(), so that readers either observe a fully linked list or are deferred until the in-flight mutation completes. The two early-return paths in teql_master_xmit() are updated to release the RCU-bh read-side critical section before returning, since leaving it held would disable BH on that CPU for good.

The advisory is available at git.kernel.org. This vulnerability was named CVE-2026-72390 since 08/09/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $5k-$25k at the moment (estimation calculated on 08/15/2026).

Upgrading to version 6.1.178, 6.6.145, 6.12.97, 6.18.40, 7.1.5 or 7.2-rc2 eliminates this vulnerability. Applying the patch 03c67781254c574ae7fa75e881239a78473bdf42/735567bde7401f82b064f9f107b52ee1bf84ed8c/11402e6e18e96df615cbcc58157818dd604b23ff/9b7d05cbaa60108642402100efa6aa288dd33023/b26aa9d993537a4c3167d8ceead3b7c69c3a0aac/e5b811fe793166aecc59b085c1b7c31262ef2316 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: 10.0
VulDB Meta Temp Score: 9.5

VulDB Base Score: 10.0
VulDB Temp Score: 9.5
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: Use after free
CWE: CWE-416 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

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 6.1.178/6.6.145/6.12.97/6.18.40/7.1.5/7.2-rc2
Patch: 03c67781254c574ae7fa75e881239a78473bdf42/735567bde7401f82b064f9f107b52ee1bf84ed8c/11402e6e18e96df615cbcc58157818dd604b23ff/9b7d05cbaa60108642402100efa6aa288dd33023/b26aa9d993537a4c3167d8ceead3b7c69c3a0aac/e5b811fe793166aecc59b085c1b7c31262ef2316

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-2026-72390 (🔒)
GCVE (CVE): GCVE-0-2026-72390
GCVE (VulDB): GCVE-100-390706

Entryinfo

Created: 08/15/2026 14:12
Changes: 08/15/2026 14:12 (61)
Complete: 🔍
Cache ID: 216::103

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