Resource exhaustion in Ffmpeg

CVE-2026-66037

FFmpeg through 8.1.2, fixed in commit 5d7112c, contains an uncontrolled resource consumption vulnerability in the IAMF demuxer that allows an unauthenticated attacker to cause multi-gigabyte memory allocation from a 17-byte input file by supplying a crafted count_label field. The mix_presentation_obu() function in libavformat/iamf_parse.c calls av_calloc(count_label, sizeof(*language_label)) with an attacker-controlled value before validating available OBU data, enabling an allocation amplification of approximately 126 million bytes per input byte that exhausts process memory or triggers an OOM-kill during format probing.

EPSS: 0.002 (11.3th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H.

Affected products

  • Ffmpeg — versions 0, 86708357d126af84c16f80d9c57335d1e8c845c5

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-66037?
CVE-2026-66037 is a medium-severity vulnerability in Ffmpeg, classified under Allocation of Resources Without Limits or Throttling. CVSS score: 6.5/10. Published 2026-07-24.
How severe is CVE-2026-66037?
Medium severity. CVSS v3 base score is 6.5 out of 10.