Linux Kernel up to 7.1.2 F2fs f2fs_read_data_large_folio denial of service

Summaryinfo

A vulnerability labeled as critical has been found in Linux Kernel up to 7.1.2. Affected by this issue is the function f2fs_read_data_large_folio of the component F2fs. The manipulation results in denial of service. This vulnerability is reported as CVE-2026-63820. The attack can be launched remotely. No exploit exists.

Detailsinfo

A vulnerability classified as critical has been found in Linux Kernel up to 7.1.2. Affected is the function f2fs_read_data_large_folio of the component F2fs. The manipulation with an unknown input leads to a denial of service vulnerability. CWE is classifying the issue as CWE-404. The product does not release or incorrectly releases a resource before it is made available for re-use. This is going to have an impact on availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: f2fs: fix missing read bio submission on large folio error f2fs_read_data_large_folio() can keep a read bio across multiple readahead folios. If a later folio hits an error before any of its blocks are added to the bio, folio_in_bio is false and the current error path returns immediately after ending that folio. This can leave the bio accumulated for earlier folios unsubmitted. Those folios then never receive read completion, and readers can wait indefinitely on the locked folios. Route errors through the common out path so any pending bio is submitted before returning. Stop consuming more readahead folios once an error is seen, and only wait on and clear the current folio when it was actually added to the bio.

The advisory is available at git.kernel.org. This vulnerability is traded as CVE-2026-63820 since 07/19/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 07/19/2026). This vulnerability is assigned to T1499 by the MITRE ATT&CK project.

Upgrading to version 7.1.3 or 7.2-rc1 eliminates this vulnerability.

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Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 7.1.0
• 7.1.1
• 7.1.2

License

• open-source

Website

• Vendor: https://www.kernel.org/

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