CVE-2026-64361: hfs/hfsplus: fix u32 overflow in check_and_correct_requested_length

Severity: high (CVSS 7.8 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: 2026-07-25 · updated 2026-09-04
Weakness: CWE-191

Description

In the Linux kernel, the following vulnerability has been resolved: hfs/hfsplus: fix u32 overflow in check_and_correct_requested_length check_and_correct_requested_length() compares (off + len) against node_size using u32 arithmetic. When the caller passes a large len value (e.g. from an underflowed subtraction in hfs_brec_remove()), off + len can wrap past 2^32 and produce a small result, causing the bounds check to pass when it should fail. For example, with off=14 and len=0xFFFFFFF2 (underflowed from data_off - keyoffset - size in hfs_brec_remove), off + len wraps to 6, which is less than a typical node_size of 512, so the check passes and the subsequent memmove reads ~4GB past the node buffer. Fix this by widening the addition to u64 before comparing against node_size. This prevents the u32 wrap while keeping the logic straightforward.

Affected products

Linux kernel: from 5.4.297 before 5.5; from 5.10.241 before 5.10.261; from 5.15.190 before 5.15.212; from 6.1.149 before 6.1.178; from 6.6.103 before 6.6.145; from 6.12.43 before 6.12.97 — fixed in 5.10.261, 5.15.212, 5.5, 6.1.178, 6.12.97, 6.16

How to fix

Upgrade to a fixed version: Linux kernel 5.10.261, 5.15.212, 5.5, 6.1.178. Check the vendor advisory for mitigations.

References

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