libfsapfs through 20260921 Heap Out-of-Bounds Read via libfsapfs_key_encrypted_key_read_data

Advisories

libfsapfs through 20260921 Heap Out-of-Bounds Read via libfsapfs_key_encrypted_key_read_data

Severity: medium
Date: 10/15/2026
Affecting: libfsapfs <= 20260921
CVE: CVE-2026-111133
CWE: CWE-125 Out-of-bounds Read
CVSS: 6.9
CVSS V4 Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:L/VI:N/VA:H/SC:N/SI:N/SA:N
References: https://hackmd.io/@haind-pwn/libfsapfs-key-encrypted-key-attribute-oob-read
https://github.com/libyal/libfsapfs/blob/4c7c1c21f3cfc7d35f0b34b8a47f1f1562d27bbb/libfsapfs/libfsapfs_key_encrypted_key.c#L321-L333
https://github.com/libyal/libfsapfs/blob/4c7c1c21f3cfc7d35f0b34b8a47f1f1562d27bbb/libfsapfs/libfsapfs_key_encrypted_key.c#L528-L540
https://github.com/libyal/libfsapfs
Credit: HaiND from the Post and Telecommunication Institute of Technology
Description: libfsapfs through 20260921 contains an integer underflow in libfsapfs_key_encrypted_key_read_data() that allows attackers to trigger heap out-of-bounds reads via crafted KEK attributes. Attackers can supply a crafted encrypted APFS image with malformed HMAC or wrapped KEK attribute lengths to crash fsapfsinfo, pyfsapfs, dfVFS or plaso and read adjacent heap memory before password checks.

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