CVE-2026-120243
FFmpeg 2.0 through 9.0.2 Information Disclosure via G2M Kempf Palette
What happened?
FFmpeg 2.0 through 9.0.2 contains a use of uninitialized variable vulnerability in the Go2Meeting decoder that allows attackers to leak stack memory through out-of-range palette indices. Attackers can craft a G2M3/G2M4 stream with a short Kempf palette so kempf_restore_buf() copies uninitialized stack bytes, including pointers or stack guards, into decoded output.
Affected software and versions
| Software | Version information | Fixed version |
|---|---|---|
| FFmpegFFmpeg | affected: 2.0 to ≤ 9.0.2 | See vendor advisory |
Version information comes from the source record and can include unaffected products and exceptions. Distribution packages may contain backported fixes: an older upstream version alone does not prove a server is affected.
Is it being exploited?
This CVE was not listed in the CISA catalogue at our last retrieval. This does not establish that exploitation is absent.
How to respond
- Confirm the product, installed package version, and any configuration requirements in the vendor advisory.
- Follow the vendor’s remediation or workaround guidance in the references below. Structured fixed-version data is unavailable here; the publisher’s description may include a fix or workaround.
- Restart affected services if required, then verify the running version. Known exploitation may warrant investigation as well as patching.
Sources and remediation references
- https://www.cve.org/CVERecord?id=CVE-2026-120243
- https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/24858
- https://github.com/FFmpeg/FFmpeg/commit/edad2d0dafcf44fa315eab716fd0183ce808053b
- https://github.com/FFmpeg/FFmpeg/blob/n9.0.2/libavcodec/g2meet.c#L1040-L1042
- https://github.com/FFmpeg/FFmpeg
- https://www.vulncheck.com/advisories/ffmpeg-2.0-through-9.0.2-information-disclosure-via-g2m-kempf-palette