CVE-2026-46094: ext4: fix bounds check in check_xattrs() to prevent out-of-bounds access

Severity: high (CVSS 7.1 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-05-27 · updated 2026-06-25
Weakness: CWE-125

Description

In the Linux kernel, the following vulnerability has been resolved: ext4: fix bounds check in check_xattrs() to prevent out-of-bounds access The bounds check for the next xattr entry in check_xattrs() uses (void *)next >= end, which allows next to point within sizeof(u32) bytes of end. On the next loop iteration, IS_LAST_ENTRY() reads 4 bytes via *(__u32 *)(entry), which can overrun the valid xattr region. For example, if next lands at end - 1, the check passes since next < end, but IS_LAST_ENTRY() reads 4 bytes starting at end - 1, accessing 3 bytes beyond the valid region. Fix this by changing the check to (void *)next + sizeof(u32) > end, ensuring there is always enough space for the IS_LAST_ENTRY() read on the subsequent iteration.

Affected products

Linux kernel: from 6.3 before 6.6.140; from 6.7 before 6.12.86; from 6.13 before 6.18.27; from 6.19 before 7.0.4 — fixed in 6.12.86, 6.18.27, 6.6.140, 7.0.4

How to fix

Upgrade to a fixed version: Linux kernel 6.12.86, 6.18.27, 6.6.140, 7.0.4. Check the vendor advisory for mitigations.

References

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