What is CVE-2026-62377?
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.
The record classifies CVE-2026-62377 under weakness classes CWE-617, CWE-908. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs no prior authentication, needs a user to take an action first. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 48 days ago.
Severity and exploitation probability
- CVSS v3.1 base score
- 4.3 — MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:L - EPSS (FIRST)
- 0.4% probability of exploitation in the next 30 days, higher than 34.1% of all scored CVEs
- CISA KEV
- Not listed in the CISA Known Exploited Vulnerabilities catalog
- Threadlinqs priority
- 5.5/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- Published
- 2026-08-18, last modified 2026-08-19
Is CVE-2026-62377 being exploited?
Weaponised exploit code for CVE-2026-62377 is publicly available. 1 public proof-of-concept repository is tracked for this identifier. It currently carries a trending score of 46 in the Threadlinqs vulnerability feed.
- trickest/cve (trickest)
Affected products and versions
- strukturag: libheif
How to fix CVE-2026-62377
No vendor patch reference has been recorded for CVE-2026-62377 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.
Threat activity tracking CVE-2026-62377
No threat campaign in the Threadlinqs corpus currently references CVE-2026-62377, in its CVE list or as an indicator. The linkage is recomputed from the live corpus on every daily ingest, so this section fills in as soon as a tracked campaign cites the identifier.
Sources
Enriched from CVE.org, NVD, FIRST EPSS, public proof-of-concept repositories. Last verified by Threadlinqs on . This product uses the NVD API but is not endorsed or certified by the NVD.