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.
References6
- github.com/libyal/libfsapfs
- github.com/libyal/libfsapfs/blob/4c7c1c21f3cfc7d35f0b34b8a47f1f…
- github.com/libyal/libfsapfs/blob/4c7c1c21f3cfc7d35f0b34b8a47f1f…
- hackmd.io/@haind-pwn/libfsapfs-key-encrypted-key-attribute-oob-…
- www.vulncheck.com/advisories/libfsapfs-through-20260921-heap-ou…
- hackmd.io/@haind-pwn/libfsapfs-key-encrypted-key-attribute-oob-…
Metrics
- CVSS 3.1
-
6.1
MEDIUM
Score source: CNA
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:H - CVSS 4.0
-
6.9
MEDIUM
Score source: CNA
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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - EPSS — exploit probability
- 0% percentile: 10 · as of 10 November 2026
- CWE
- CWE-125
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.