CVE-2026-125250: Heap Overflow (CVSS 7.8)

Description

FFmpeg through 9.0.2 contains a heap buffer overflow in the GIF encoder's gif_image_write_image() in libavcodec/gif.c because shrunk_buf is sized from the first frame's linesize. Attackers can supply PAL8 video whose frame linesize grows mid-stream, causing remap_frame_to_palette() to write past shrunk_buf and corrupt the heap during GIF transcoding.

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CVSS v3.1 Score

7.8

HIGH

CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

EPSS — Exploit Prediction

0.0014

Probability of exploitation

0.04%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-122 CWE-122

References

Other References

https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/25690 https://github.com/FFmpeg/FFmpeg https://github.com/FFmpeg/FFmpeg/blob/n9.0.2/libavcodec/gif.c#L405 https://github.com/FFmpeg/FFmpeg/commit/26c2980980295e5516f308c5a2792d2a72e43eae https://www.vulncheck.com/advisories/ffmpeg-through-9.0.2-gif-encoder-heap-buffer-overflow-via-shrunk-buf-remap

Frequently Asked Questions

What is CVE-2026-125250? +

FFmpeg through 9.0.2 contains a heap buffer overflow in the GIF encoder's gif_image_write_image() in libavcodec/gif.c because shrunk_buf is sized from the first frame's linesize. Attackers can supply PAL8 video whose frame linesize grows mid-stream, causing remap_frame_to_palette() to write past shrunk_buf and corrupt the heap during GIF transcoding. It has a CVSS v3.1 base score of 7.8 (HIGH).

How severe is CVE-2026-125250? +

CVE-2026-125250 has a CVSS v3.1 score of 7.8 out of 10, rated HIGH. This is a high-severity vulnerability that should be prioritized for patching. The EPSS score is 0.0014, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-125250? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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