# CVE-2026-54241: libde265 heap buffer overflow in sample adaptive offset filter

Source: https://junglewise.ai/threats/cve-2026-54241-libde265-heap-buffer-overflow-in-sample-adaptive-offset-filter  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-09-11. Updated: 2026-09-26  
License: CC BY 4.0 with a link back

CVE-2026-54241 · Severity: high · CVSS 7.4 · Published 2026-09-11

libde265 is a widely-used open-source H.265 video codec library used by popular media applications including VLC, GStreamer, and GNOME image viewers. A flaw in its sample adaptive offset filter allows a specially crafted video file to trigger an integer overflow, resulting in undersized memory allocation and out-of-bounds reading from the heap—potentially exposing sensitive data in decoded video output or crashing the application.

## Quick answers

**Is CVE-2026-54241 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-54241 being exploited in the wild.

**How severe is CVE-2026-54241?** High severity, with a CVSS score of 7.4, published 11 September 2026.

**Which products and versions are affected?** strukturag libde265 prior to 1.1.1.

**Is there a fix for CVE-2026-54241?** A patch was published on 2026-06-03: Version 1.1.1 contains patch Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-54241 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-54241?** Check whether anything you run is named in the advisory. 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 exists in the apply_sample_adaptive_offset_sequential() function in libde265/sao.cc, where a signed 32-bit integer overflow occurs when calculating the SAO input buffer size (stride × height × bytes_per_pixel). With large HEVC dimensions (e.g., 46341×46341 pixels at 16-bit color depth), this calculation wraps to a small positive value, causing undersized heap allocation. The SAO filter then performs reads using the actual (non-overflowed) stride value, reading up to ~4.3 GB past a ~625 KB buffer. Attack requires a crafted HEVC bitstream with specific SPS parameters, no user interaction or authentication. The fix widens the calculation to 64-bit (size_t). Patched in version 1.1.1.

## Affected products

- strukturag libde265 prior to 1.1.1

## Timeline

- 2026-06-03: disclosed: GitHub Security Advisory GHSA-j2qq-x2xq-g9wr published
- 2026-09-11: advisory: CVE-2026-54241 published on NVD
- 2026-06-03: patched: Version 1.1.1 contains patch

## References

- [https://github.com/strukturag/libde265/security/advisories/GHSA-j2qq-x2xq-g9wr](https://github.com/strukturag/libde265/security/advisories/GHSA-j2qq-x2xq-g9wr)