Out-of-bounds write in libheif - #VU146728
Published: September 2, 2026
Vulnerability identifier: #VU146728
CSH Severity: High
CVSS v4: 9.3 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]
CVE-ID: N/A
CWE-ID: CWE-787
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to execute arbitrary code.
The vulnerability exists due to out-of-bounds write in the built-in `unci` mixed-interleave decoder when parsing a crafted uncompressed-image file with unequal chroma bit depths. A remote attacker can supply a specially crafted HEIF image to execute arbitrary code.
Only builds with `WITH_UNCOMPRESSED_CODEC=ON` are vulnerable. The issue is internal to libheif's `unci` decoder and does not require external codecs. The demonstrated code-execution and file-disclosure impacts were build- and deployment-specific rather than universal.
Affected software
libheif
Remediation
Install security update from vendor's website.
libheif - update to 1.23.3