# CVE-2026-84447: libheif reference amplification denial of service

Source: https://junglewise.ai/threats/cve-2026-84447-libheif-is-a-heif-and-avif-file-format-decoder-and-encoder-in-1  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-18. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-84447 · Severity: high · CVSS 7.5 · Published 2026-09-18

libheif is a decoder and encoder for HEIF and AVIF image formats used in image processing and media applications. In versions 1.23.1 and earlier, specially crafted image files with nested reference chains (grid, iovl, and iden structures) can cause excessive CPU and memory usage, allowing an attacker to trigger a denial of service by making the application hang or crash when processing a malicious file.

Technologies: [Strukturag Libheif](https://junglewise.ai/threats/technologies/strukturag-libheif). Vendors: [Strukturag](https://junglewise.ai/threats/vendors/strukturag).

## Quick answers

**Is CVE-2026-84447 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-84447 being exploited in the wild.

**How severe is CVE-2026-84447?** High severity, with a CVSS score of 7.5, published 18 September 2026.

**Which products and versions are affected?** Strukturag Libheif 1.23.1 and earlier.

**Is there a fix for CVE-2026-84447?** A patch was published on 2026-08-25: Fix released in libheif v1.23.2 Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-84447 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-84447?** Check whether you run Strukturag Libheif at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Technical details

The vulnerability is a resource amplification bug in derived-image reference handling where the cycle-detection set (processed_ids) is passed by value per branch, causing the same base image to be decoded repeatedly along different paths through the reference graph. An attacker can construct deeply nested or widely branching reference structures that exponentially multiply decode operations and memory consumption, bypassing decode caching and operation budgets. The fix (v1.23.2) introduces a shared per-traversal decode operation budget, depth guards, and memoization to bound the exponential blow-up.

## Affected products

- strukturag libheif 1.23.1 and earlier

## Timeline

- 2026-08-25: patched: Fix released in libheif v1.23.2
- 2026-09-18: disclosed: CVE-2026-84447 and GHSA-x8xm-cm2c-cfc8 published

## References

- [https://github.com/strukturag/libheif/commit/30b52a4e829efe0ee6d7208e8500b99f664af5e9](https://github.com/strukturag/libheif/commit/30b52a4e829efe0ee6d7208e8500b99f664af5e9)
- [https://github.com/strukturag/libheif/releases/tag/v1.23.2](https://github.com/strukturag/libheif/releases/tag/v1.23.2)

## Related threats

- [libheif heap buffer overflow in unc_decoder_mixed_interleave](https://junglewise.ai/threats/cve-2026-120208-libheif-1-18-0-before-1-23-3-contains-a-heap-based-buffer)
- [libheif integer overflow in uncompressed tile range check](https://junglewise.ai/threats/cve-2026-84451-libheif-is-a-heif-and-avif-file-format-decoder-and-encoder-from-1)
- [libheif assertion failure in clap property crop calculation](https://junglewise.ai/threats/cve-2026-84450-libheif-is-a-heif-and-avif-file-format-decoder-and-encoder-from-1)
- [libheif heap out-of-bounds read in inline-mask region API](https://junglewise.ai/threats/cve-2026-84448-libheif-is-a-heif-and-avif-file-format-decoder-and-encoder-prior)
- [libheif sequence timing denial of service and memory exhaustion](https://junglewise.ai/threats/cve-2026-84446-libheif-is-a-heif-and-avif-file-format-decoder-and-encoder-prior)