CVE-2023-54062: ext4: fix invalid free tracking in ext4_xattr_move_to_block()

Severity: high (CVSS 7.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-12-24 · updated 2026-10-15

Description

In the Linux kernel, the following vulnerability has been resolved: ext4: fix invalid free tracking in ext4_xattr_move_to_block() In ext4_xattr_move_to_block(), the value of the extended attribute which we need to move to an external block may be allocated by kvmalloc() if the value is stored in an external inode. So at the end of the function the code tried to check if this was the case by testing entry->e_value_inum. However, at this point, the pointer to the xattr entry is no longer valid, because it was removed from the original location where it had been stored. So we could end up calling kvfree() on a pointer which was not allocated by kvmalloc(); or we could also potentially leak memory by not freeing the buffer when it should be freed. Fix this by storing whether it should be freed in a separate variable.

Affected products

Linux kernel: from 4.14.308 before 4.14.315; from 4.19.276 before 4.19.283; from 5.4.235 before 5.4.243; from 5.10.173 before 5.10.180; from 5.15.99 before 5.15.112; from 6.1.16 before 6.1.29 — fixed in 4.14.315, 4.19.283, 5.10.180, 5.15.112, 5.4.243, 6.1.29

How to fix

Upgrade to a fixed version: Linux kernel 4.14.315, 4.19.283, 5.10.180, 5.15.112. Check the vendor advisory for mitigations.

References

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