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Vulnerability · Published Aug 18, 2026 · Assigned by GitHub_M

CVE-2026-62377libheif: Reachable assertion in HeifContext::get_track() aborts on a valid-but-empty HEIF sequence file (context.cc:2110)

Medium 4.3

In plain English

A medium-severity security flaw in libheif from strukturag. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 36% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)4.3Medium
Exploit odds (30 days)0.4%top 64.2% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

libheif is a HEIF and AVIF file format decoder and encoder. In 1.23.0 and earlier, a crafted HEIF sequence accepted by heif_context_read_from_memory() can leave the context with no registered sequence tracks and crash when heif_context_get_track(ctx, 0) is called. HeifContext::get_track() in libheif/context.cc executes assert(has_sequence()) before its normal error handling, so assert-enabled builds abort instead of allowing the public wrapper in libheif/api/libheif/heif_sequences.cc to return null. In release builds, removing the assertion lets the track_id zero path dereference m_tracks.begin()->second on an empty map, which is undefined behavior and typically crashes. The issue is reachable through documented public APIs after parsing attacker-controlled bytes. This issue is fixed in version 1.23.1.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:14libheif1.23.1-1DEBIAN-CVE-2026-62377
Ubuntu:26.04:LTSlibheif1.21.2-3ubuntu0.5UBUNTU-CVE-2026-62377
Ubuntu:26.04:LTSlibheif1.21.2-3ubuntu0.5USN-8774-1

Affected products (as reported)

VendorProductVersions
strukturag libheif < 1.23.1

Weakness: CWE-617, CWE-908 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L

References