Linux Kernel up to 7.1.4 ocfs2 ocfs2_remove_refcount_extent out-of-bounds write

Summaryinfo

A vulnerability, which was classified as very critical, was found in Linux Kernel up to 7.1.4. Impacted is the function ocfs2_remove_refcount_extent of the component ocfs2. Such manipulation leads to out-of-bounds write. This vulnerability is documented as CVE-2026-80638. The attack can be executed remotely. There is not any exploit available.

Detailsinfo

A vulnerability was found in Linux Kernel up to 7.1.4. It has been rated as very critical. Affected by this issue is the function ocfs2_remove_refcount_extent of the component ocfs2. The manipulation with an unknown input leads to a out-of-bounds write vulnerability. Using CWE to declare the problem leads to CWE-787. The product writes data past the end, or before the beginning, of the intended buffer. Impacted is confidentiality, integrity, and availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: ocfs2: fix out-of-bounds write in ocfs2_remove_refcount_extent [BUG] Unlinking a refcounted file whose refcount tree has leaf blocks triggers a fortify panic due to an out-of-bounds write. [CAUSE] When the last leaf block is removed from a refcount tree, ocfs2_remove_refcount_extent() converts the root back to leaf mode with a bulk memset on &rb->rf_records. rf_records sits in an anonymous union with rf_list. rf_list.l_tree_depth aliases rf_records.rl_count, and is 0 for a single-level tree. With rl_count equal to 0, the memset writes past the 16-byte declared size of rf_records, which the fortify checker catches. [FIX] Replace the bulk memset on &rb->rf_records with a correctly-bounded memset on rl_recs[] alone, after setting rl_count to the correct value.

The advisory is available at git.kernel.org. This vulnerability is handled as CVE-2026-80638 since 08/26/2026. The exploitation is known to be easy. The attack may be launched remotely. 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 08/28/2026).

Upgrading to version 7.1.5 eliminates this vulnerability. Applying the patch f5255516ec7add3a6d5d37853ad5a9a9ddb14305/1ec3cca2d8b6b9ff6584ca626d4c8918bbf48d44 is able to eliminate this problem.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 7.1.0
• 7.1.1
• 7.1.2
• 7.1.3
• 7.1.4

License

• open-source

Website

• Vendor: https://www.kernel.org/

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