Linux Kernel up to 6.6.135/6.12.82/6.18.23/6.19.13 ocfs2 ocfs2_validate_inode_block use after free

CVSS Meta Temp Score
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CTI Interest Score
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7.7$5k-$25k0.00

Summaryinfo

A vulnerability has been found in Linux Kernel up to 6.6.135/6.12.82/6.18.23/6.19.13 and classified as critical. The affected element is the function ocfs2_validate_inode_block of the component ocfs2. The manipulation leads to use after free. This vulnerability is documented as CVE-2026-43076. There is not any exploit available. The affected component should be upgraded.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.6.135/6.12.82/6.18.23/6.19.13 and classified as critical. This issue affects the function ocfs2_validate_inode_block of the component ocfs2. The manipulation with an unknown input leads to a use after free vulnerability. Using CWE to declare the problem leads to CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: ocfs2: validate inline data i_size during inode read When reading an inode from disk, ocfs2_validate_inode_block() performs various sanity checks but does not validate the size of inline data. If the filesystem is corrupted, an inode's i_size can exceed the actual inline data capacity (id_count). This causes ocfs2_dir_foreach_blk_id() to iterate beyond the inline data buffer, triggering a use-after-free when accessing directory entries from freed memory. In the syzbot report: - i_size was 1099511627576 bytes (~1TB) - Actual inline data capacity (id_count) is typically <256 bytes - A garbage rec_len (54648) caused ctx->pos to jump out of bounds - This triggered a UAF in ocfs2_check_dir_entry() Fix by adding a validation check in ocfs2_validate_inode_block() to ensure inodes with inline data have i_size <= id_count. This catches the corruption early during inode read and prevents all downstream code from operating on invalid data.

The advisory is shared at git.kernel.org. The identification of this vulnerability is CVE-2026-43076 since 05/01/2026. The exploitation is known to be easy. Technical details are known, but no exploit is available. The price for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 07/05/2026).

The vulnerability scanner Nessus provides a plugin with the ID 325059 (Debian dla-4665 : affs-modules-6.1.0-48-4kc-malta-di - security update), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.6.136, 6.12.83, 6.18.24 or 6.19.14 eliminates this vulnerability. Applying the patch 37f074e65f24f10f8d8df224a572e4cb9e6faf63/c1de19e891be3bfb3e1d0c7cf07bbb8fb3b77c1b/cd2d765aa7157f852999842af32148128c735d39/77d0295725109d77f5854ef5b58c0d06c08168cc/1524af3685b35feac76662cc551cbc37bd14775f is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (325059) and CERT Bund (WID-SEC-2026-1385). If you want to get the best quality for vulnerability data then you always have to consider VulDB.

Affected

  • Google Container-Optimized OS
  • Debian Linux
  • Red Hat Enterprise Linux
  • Ubuntu Linux
  • SUSE Linux
  • Oracle Linux
  • SUSE openSUSE
  • Open Source Linux Kernel
  • RESF Rocky Linux
  • Microsoft Azure Linux

Productinfo

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Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 7.9
VulDB Meta Temp Score: 7.7

VulDB Base Score: 8.0
VulDB Temp Score: 7.6
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 7.8
CNA Vector (Linux): 🔒

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
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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: Partially
Local: Yes
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 325059
Nessus Name: Debian dla-4665 : affs-modules-6.1.0-48-4kc-malta-di - security update

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.6.136/6.12.83/6.18.24/6.19.14
Patch: 37f074e65f24f10f8d8df224a572e4cb9e6faf63/c1de19e891be3bfb3e1d0c7cf07bbb8fb3b77c1b/cd2d765aa7157f852999842af32148128c735d39/77d0295725109d77f5854ef5b58c0d06c08168cc/1524af3685b35feac76662cc551cbc37bd14775f

Timelineinfo

05/01/2026 CVE reserved
05/06/2026 +5 days Advisory disclosed
05/06/2026 +0 days VulDB entry created
07/05/2026 +60 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-43076 (🔒)
GCVE (CVE): GCVE-0-2026-43076
GCVE (VulDB): GCVE-100-361301
CERT Bund: WID-SEC-2026-1385 - Linux Kernel: Mehrere Schwachstellen

Entryinfo

Created: 05/06/2026 11:51
Updated: 07/05/2026 22:05
Changes: 05/06/2026 11:51 (59), 05/07/2026 03:05 (7), 05/21/2026 01:54 (11), 06/08/2026 14:51 (1), 07/05/2026 22:05 (2)
Complete: 🔍
Cache ID: 216::103

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