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Advisory severityMediumRed Hat Linux

Medium [CVE-2026-63818] validate orphan inode entry count

This medium-severity Red Hat Linux advisory covers CVE-2026-63818.

Aggregated and source-linked by VulniPulse. Data sources, validation and limitations.

CVE-2026-63818 Source published Source updated

VulniPulse record published Record updated

CVE-2026-63818
Affected products & platforms
Red Hat LinuxUnclassified
Open source advisory

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Summary

In the Linux kernel, the following vulnerability has been resolved: f2fs: validate orphan inode entry count f2fs_recover_orphan_inodes() trusts the orphan block entry_count when replaying orphan inodes from the checkpoint pack.

A corrupted entry_count larger than F2FS_ORPHANS_PER_BLOCK makes the recovery loop read past the ino[] array and interpret footer or following data as inode numbers. On a crafted image, mounting an unpatched kernel can drive orphan recovery into f2fs_bug_on() and panic the kernel.

Validate entry_count before consuming entries so corrupted checkpoint data fails the mount with -EFSCORRUPTED and requests fsck instead. Set ERROR_INCONSISTENT_ORPHAN as well, so the corruption reason can be recorded in the superblock s_errors[] field.

This gives fsck a persistent hint even though mount-time orphan recovery failure may leave no chance to persist SBI_NEED_FSCK through a checkpoint. A flaw was found in the Linux kernel's F2FS (Flash-Friendly File System) component.

This vulnerability arises from improper validation of the orphan inode entry count during the recovery process. A local attacker could craft a malicious F2FS image, which, when mounted on an unpatched system, could lead to a kernel panic, resulting in a Denial of Service (DoS).

The system would become unresponsive, requiring a restart. Red Hat severity: Moderate.

Weakness: CWE-125.

Affected versions

No affected-version range was extracted from the source record. The vendor advisory is authoritative. Check it before change work.

Official advisory · medium-confidence parse· fetched 8 days ago·verify at source

Fixed versions

No fixed release is recorded yet. That does not prove no patch exists. Confirm against the vendor advisory.

Official advisory · medium-confidence parse· fetched 8 days ago·verify at source

Mitigation

The source record does not include mitigation steps. That does not mean no fix exists. Read the vendor advisory below for the authoritative guidance.

Official advisory · medium-confidence parse· fetched 8 days ago·verify at source

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