CVE-2026-84384 is a high-severity (CVSS 7.5) CWE-409 vulnerability. No vendor fix is recorded yet; mitigation options are listed below.
libheif is a HEIF and AVIF file format decoder and encoder. From 1.19.0 until 1.23.2, crafted HEIF or AVIF mime metadata and unci image data can cause decompress_brotli() and do_inflate()…
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
Exploitation and automatability from CISA’s SSVC triage for CVE-2026-84384.
Description
libheif is a HEIF and AVIF file format decoder and encoder. From 1.19.0 until 1.23.2, crafted HEIF or AVIF mime metadata and unci image data can cause decompress_brotli() and do_inflate() to grow accumulated output without an effective size limit or MemoryHandle accounting. The brotli path has no output bound, while the zlib path checks only a small temporary buffer in a branch that valid streams do not reach, and overlapping icef units can decompress the same payload repeatedly. HeifContext::interpret_heif_file_images() processes multiple compressed metadata items during file opening, allowing a small file to consume unbounded memory and terminate the process. This issue is fixed in version 1.23.2.
Detection & mitigation playbook
VulnerabilityDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for the affected component, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Remediation status
No patched version of the affected component has shipped for CVE-2026-84384 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
Mitigate without a patch
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2026-84384 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2026-84384. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-84384 in your dependencies?
O3 Security finds CVE-2026-84384 across dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.