Linux Kernel up to 7.2.4 batman-adv batadv_bla_del_backbone_claims use after free

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
9.5	$5k-$25k	0.43-

Summaryinfo

A vulnerability classified as very critical was found in Linux Kernel up to 7.2.4. Affected by this issue is the function batadv_bla_del_backbone_claims of the component batman-adv. The manipulation results in use after free. This vulnerability is identified as CVE-2026-89948. The attack can be executed remotely. There is not any exploit available. Upgrading the affected component is advised.

Detailsinfo

A vulnerability classified as very critical has been found in Linux Kernel up to 7.2.4. Affected is the function batadv_bla_del_backbone_claims of the component batman-adv. The manipulation with an unknown input leads to a use after free vulnerability. CWE is classifying the issue as CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: batman-adv: bla: fix freeing of claims on meshif deletion When the mesh interface is getting deleted, then batadv_bla_del_backbone_claims() (via batadv_bla_purge_backbone_gw()) could make sure that all claims gets removed. But this function is only executed when bat_priv->bla.claim_hash is not NULL. And since batadv_bla_free() is always setting it to NULL before it is (indirectly) called, it was never actually executed. But the batadv_bla_purge_claims() -> batadv_handle_unclaim() is at the moment too fragile because the BLA code is not handling the rehashing in batadv_bla_update_orig_address(). The stored backbone address doesn't have to be the one actually used for the hash bucket selection during the initial adding of the backbone. The batadv_handle_unclaim() can therefore fail to find the respective backbone for the unclaim and then stop the deletion. But the actual backbone_gw object is not needed for the unclaim because all relevant information is always provided by the caller. And the check for the existence of the backbone_gw doesn't provide any additional security check for the deletion of a claim.

The advisory is available at git.kernel.org. This vulnerability is traded as CVE-2026-89948 since 09/11/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation doesn't require any form of authentication. 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 09/16/2026).

Upgrading to version 5.10.270, 5.15.221, 6.1.188, 6.6.157, 6.12.110, 6.18.51, 7.2.5 or 7.3-rc1 eliminates this vulnerability. Applying the patch 844a95a734f178d56c7acce14c5cce2cecff7e1a/baeb1a28fd8e2f68193650d3664a8cd1adfd85c6/aacffa780a37e06cd5a13d33740a6e96c3a67e6c/76aedcde5a2489cc971d4d1e396e784a49565e96/f50edb69082a8ba990cc23d642089829f99afe6a/871acdf97f64cee8398f72b88b89e8b4f4816dbe/9a0c47023d3254048a1588534755d4476bcc3abc/8d128c932bced74e3b1625ba3d7c78ef122a88a7 is able to eliminate this problem. The best possible mitigation is suggested to be upgrading to the latest version.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 5.10.269
• 5.15.220
• 6.1.187
• 6.6.156
• 6.12.109
• 6.18.0
• 6.18.1
• 6.18.2
• 6.18.3
• 6.18.4
• 6.18.5
• 6.18.6
• 6.18.7
• 6.18.8
• 6.18.9
• 6.18.10
• 6.18.11
• 6.18.12
• 6.18.13
• 6.18.14
• 6.18.15
• 6.18.16
• 6.18.17
• 6.18.18
• 6.18.19
• 6.18.20
• 6.18.21
• 6.18.22
• 6.18.23
• 6.18.24
• 6.18.25
• 6.18.26
• 6.18.27
• 6.18.28
• 6.18.29
• 6.18.30
• 6.18.31
• 6.18.32
• 6.18.33
• 6.18.34
• 6.18.35
• 6.18.36
• 6.18.37
• 6.18.38
• 6.18.39
• 6.18.40
• 6.18.41
• 6.18.42
• 6.18.43
• 6.18.44
• 6.18.45
• 6.18.46
• 6.18.47
• 6.18.48
• 6.18.49
• 6.18.50
• 7.2.0
• 7.2.1
• 7.2.2
• 7.2.3
• 7.2.4

License

• open-source

Website

• Vendor: https://www.kernel.org/

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

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

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: 🔒

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 5.10.270/5.15.221/6.1.188/6.6.157/6.12.110/6.18.51/7.2.5/7.3-rc1
Patch: 844a95a734f178d56c7acce14c5cce2cecff7e1a/baeb1a28fd8e2f68193650d3664a8cd1adfd85c6/aacffa780a37e06cd5a13d33740a6e96c3a67e6c/76aedcde5a2489cc971d4d1e396e784a49565e96/f50edb69082a8ba990cc23d642089829f99afe6a/871acdf97f64cee8398f72b88b89e8b4f4816dbe/9a0c47023d3254048a1588534755d4476bcc3abc/8d128c932bced74e3b1625ba3d7c78ef122a88a7

Timelineinfo

09/11/2026 CVE reserved
09/16/2026 +5 days Advisory disclosed
09/16/2026 +0 days VulDB entry created
09/16/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-89948 (🔒)
GCVE (CVE): GCVE-0-2026-89948
GCVE (VulDB): GCVE-100-405846

Entryinfo

Created: 09/16/2026 15:19
Changes: 09/16/2026 15:19 (59)
Complete: 🔍
Cache ID: 216::103

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