# CVE-2026-125265: FFmpeg use-after-free in NVIDIA codec decoding

Source: https://junglewise.ai/threats/cve-2026-125265-ffmpeg-through-9-0-2-contains-a-use-after-free-vulnerability-in  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-09. Updated: 2026-11-09  
License: CC BY 4.0 with a link back

CVE-2026-125265 · Severity: medium · CVSS 5.3 · Published 2026-11-09

FFmpeg is a multimedia processing library used in many media players and streaming applications. A use-after-free vulnerability in the NVIDIA GPU video codec decoder can allow attackers to crash applications or leak sensitive data from memory by supplying specially crafted video files.

Technologies: [Ffmpeg](https://junglewise.ai/threats/technologies/ffmpeg). Vendors: [Ffmpeg](https://junglewise.ai/threats/vendors/ffmpeg).

## Quick answers

**Is CVE-2026-125265 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-125265 being exploited in the wild.

**How severe is CVE-2026-125265?** Medium severity, with a CVSS score of 5.3, published 9 November 2026.

**Which products and versions are affected?** Ffmpeg through 9.0.2.

**Is there a fix for CVE-2026-125265?** Yes: fixed in FFmpeg 9.1. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-125265 attacked?** It is attacked over the network.

**Am I affected by CVE-2026-125265?** Check whether you run Ffmpeg 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.

## How to fix

- Fixed in FFmpeg 9.1

## Technical details

A use-after-free flaw exists in libavcodec/nvdec.c where the ff_nvdec_start_frame() function fails to reset the bitstream pointer (ctx->bitstr) when handling slice errors, allowing a subsequent picture decode to reuse freed heap memory. An attacker can craft malicious video with incomplete frames that abandon processing before end_frame is called, causing cuvidDecodePicture() to read from freed memory, leading to information disclosure or denial of service.

## Affected products

- FFmpeg FFmpeg through 9.0.2

## Timeline

- 2026-11-09: disclosed
- 2026-10-27: patched

## References

- [https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/25231](https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/25231)
- [https://github.com/FFmpeg/FFmpeg](https://github.com/FFmpeg/FFmpeg)

## Related threats

- [FFmpeg heap out-of-bounds read in v4l2_buffers](https://junglewise.ai/threats/cve-2026-125270-ffmpeg-through-9-0-2-contains-a-heap-out-of-bounds-read)
- [FFmpeg double free in H.264 SEI message handling](https://junglewise.ai/threats/cve-2026-125269-ffmpeg-through-9-0-2-contains-a-double-free-vulnerability-in)
- [FFmpeg heap out-of-bounds write in APAC decoder](https://junglewise.ai/threats/cve-2026-125267-ffmpeg-before-8-1-3-and-9-x-before-9-0-2-contains-a-heap-out-of)
- [FFmpeg JPEG XL parser uncontrolled resource consumption](https://junglewise.ai/threats/cve-2026-125264-ffmpeg-through-9-0-2-contains-an-uncontrolled-resource)
- [FFmpeg LCEVC dimension validation bypass memory exhaustion](https://junglewise.ai/threats/cve-2026-125263-ffmpeg-9-0-through-9-0-2-built-with-liblcevc-dec-fails-to)