Vulnerability · Published Oct 15, 2026 · Assigned by VulnCheck
CVE-2026-111133libfsapfs through 20260921 Heap Out-of-Bounds Read via libfsapfs_key_encrypted_key_read_data
Medium 6.1
In plain English
A medium-severity out-of-bounds read in libfsapfs from libyal. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 10% of all known vulnerabilities).
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | libfsapfs | no fix listed | DEBIAN-CVE-2026-111133 |
| Debian:13 | libfsapfs | no fix listed | DEBIAN-CVE-2026-111133 |
| Debian:14 | libfsapfs | no fix listed | DEBIAN-CVE-2026-111133 |
| Ubuntu:22.04:LTS | libfsapfs | no fix listed | UBUNTU-CVE-2026-111133 |
| Ubuntu:24.04:LTS | libfsapfs | no fix listed | UBUNTU-CVE-2026-111133 |
| Ubuntu:26.04:LTS | libfsapfs | no fix listed | UBUNTU-CVE-2026-111133 |
| Ubuntu:26.10 | libfsapfs | no fix listed | UBUNTU-CVE-2026-111133 |
Affected products (as reported)
Weakness: CWE-125 · Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H
References
- https://hackmd.io/@haind-pwn/libfsapfs-key-encrypted-key-attribute-oob-read technical-description
- https://github.com/libyal/libfsapfs/blob/4c7c1c21f3cfc7d35f0b34b8a47f1f1562d27bbb/libfsapfs/libfsapfs_key_encrypted_key.c#L321-L333 technical-description
- https://github.com/libyal/libfsapfs/blob/4c7c1c21f3cfc7d35f0b34b8a47f1f1562d27bbb/libfsapfs/libfsapfs_key_encrypted_key.c#L528-L540 technical-description
- https://github.com/libyal/libfsapfs product
- VulnCheck Advisory: libfsapfs through 20260921 Heap Out-of-Bounds Read via libfsapfs_key_encrypted_key_read_data third-party-advisory