SB2026082723 - Ubuntu update for libheif
Published: August 27, 2026
Breakdown by Severity
- Low
- Medium
- High
- Critical
Description
This security bulletin contains information about 2 vulnerabilities.
1) Integer underflow (CVE-ID: CVE-2026-62289)
CWE-ID: CWE-191 - Integer underflow
CVSSv4: 4.6 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to cause a denial of service.
The vulnerability exists due to integer underflow in the Fraction constructor when processing a crafted HEIF/AVIF file through the tiling API with process_image_transformations=1. A remote attacker can supply a specially crafted file to cause a denial of service.
User interaction is required to open the crafted file, or the issue can be triggered server-side when uploaded content is processed automatically.
2) Out-of-bounds write (CVE-ID: CVE-2026-62291)
CWE-ID: CWE-787 - Out-of-bounds write
CVSSv4: 4.6 [CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N]
The vulnerability allows a remote attacker to cause memory corruption.
The vulnerability exists due to out-of-bounds write in unc_encoder_component_interleave::encode_tile when re-encoding a decoded image with mismatched primary and auxiliary alpha plane dimensions. A remote attacker can trick the victim into opening a specially crafted HEIF sequence file and re-encoding the decoded frame to cause memory corruption.
User interaction is required to open a crafted file, and exploitation occurs through a decode and re-encode workflow using the public APIs.
Remediation
Install update from vendor's website.