CVE-2026-50142
Public exploit code is available. Proof-of-concept or working exploit code for CVE-2026-50142 is indexed in GitHub PoC. Expect opportunistic scanning and exploitation attempts — prioritize remediation even though it is not (yet) in the CISA KEV catalog.
libheif is a HEIF and AVIF file format decoder and encoder. From 1.19.0 until 1.23.0, a crafted HEIF sequence accepted by heif_context_read_from_memory() with the msf1 sequence brand can cause unbounded heap allocation. In libheif/sequences/seq_boxes.cc, Box_stsz::parse() applies max_sequence_frames only to variable-size samples, so fixed-size mode accepts an attacker-controlled sample_count without a bound. In libheif/sequences/track.cc, Track::load() also adds current_sample_idx and samples_per_chunk in 32-bit arithmetic, allowing the consistency check to be bypassed by wraparound. The resulting values reach the Chunk::Chunk() allocation path, which can consume gigabytes of memory and crash or stall the process through memory exhaustion. This issue is fixed in version 1.23.0.
CSIRTS triage
- What
- libheif has multiple vulnerabilities that could lead to denial of service or information disclosure.
- Who is affected
- Only Ubuntu 26.04 LTS deployments are affected.
- Urgency
- Remediation is urgent due to the potential for denial of service and information disclosure.
- Action
- Update to the latest version of libheif.
AI-assisted analysis generated from the source advisory — verify against the original.
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Exploitation outlook
- Low exploitation risk0.56% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 44% of all EPSS-scored CVEs.
Exploit availability
Public exploit or proof-of-concept code for CVE-2026-50142 is indexed in these free datasets. Available exploit code raises real-world risk independent of the CVSS score.
- GitHub PoCPublic proof-of-concept repositories on GitHub reference this CVE.look it up ↗
Advisory coverage (2)
- highCVE-2026-50142: libheif is a HEIF and AVIF file format decoder and encoder. From 1.19.0 until 1.23.0, a crafte…nvd · 2026-08-18
- unknownUSN-8526-1: libheif vulnerabilitiesubuntu · 2026-07-09
External references
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[](https://www.csirts.com/cve/CVE-2026-50142)