CVE-2026-66037

MEDIUMPre-NVD 6.56.5—
EchelonGraph scoreHIGH confidence

Score 6.5 from GitHub Security Advisory (severity: HIGH) published 2026-07-24. the CNA's CVSS baseline 6.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cna:vulncheck, epss, ghsa
Trending — 4 sources updated this week
6.5EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.5Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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.

CVSS v3
6.5
EG Score
6.5(high)
EG Risk
44(Track)
EG Risk 44/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity65% × 45%
Exploitation0% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
20%
KEV
Not listed

Published

July 24, 2026

Last Modified

July 28, 2026

Advisory Details (3)

Auto-updated Jul 25, 2026
No patch confirmed yet.
generic

FFmpeg IAMF Demuxer Uncontrolled Resource Consumption via mix_presentation_obu() | Advisories | VulnCheck

https://www.vulncheck.com/advisories/ffmpeg-iamf-demuxer-uncontrolled-resource-consumption-via-mix-presentation-obu
generic

#23627 - avformat/iamf_parse: check count_label against the available bytes - FFmpeg/FFmpeg - FFmpeg Forgejo

https://code.ffmpeg.org/FFmpeg/FFmpeg/pulls/23627
generic

avformat/iamf_parse: check count_label against the available bytes · 86708357d1 - FFmpeg/FFmpeg - FFmpeg Forgejo

https://code.ffmpeg.org/FFmpeg/FFmpeg/commit/86708357d126af84c16f80d9c57335d1e8c845c5

Vendor Advisories for CVE-2026-66037(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 21× in last 7d / 21× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-29 00:45 UTCEG score recompute
  2. 2026-07-29 00:45 UTCGHSA enrichment
  3. 2026-07-28 15:37 UTCEPSS rescore
  4. 2026-07-28 01:30 UTCEG score recompute
  5. 2026-07-28 01:30 UTCGHSA enrichment
  6. 2026-07-27 20:43 UTCGHSA enrichment
  7. 2026-07-27 17:20 UTCEG score recompute
  8. 2026-07-27 17:20 UTCGHSA enrichment
  9. 2026-07-27 17:02 UTCEG score recompute
  10. 2026-07-27 17:02 UTCGHSA enrichment
  11. 2026-07-27 14:14 UTCEPSS rescore
  12. 2026-07-27 02:11 UTCEG score recompute
  13. 2026-07-27 02:11 UTCGHSA enrichment
  14. 2026-07-26 14:54 UTCEPSS rescore
  15. 2026-07-26 14:54 UTCEPSS rescore
  16. 2026-07-26 02:55 UTCEG score recompute
  17. 2026-07-26 02:55 UTCGHSA enrichment
  18. 2026-07-25 14:18 UTCEPSS rescore
  19. 2026-07-25 14:18 UTCEPSS rescore
  20. 2026-07-24 19:42 UTCEG score recompute
  21. 2026-07-24 19:42 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-66037?
CVE-2026-66037 is a medium vulnerability published on July 24, 2026. 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 countlabel field. The…
When was CVE-2026-66037 disclosed?
CVE-2026-66037 was first published in the National Vulnerability Database on July 24, 2026, with the most recent update on July 28, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-66037 actively exploited?
CVE-2026-66037 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 79.5% of all scored CVEs.
What is the CVSS score of CVE-2026-66037?
CVE-2026-66037 has a CVSS v4.0 base score of 6.5 (CNA self-assessment; NVD's own analysis pending).
How do I remediate CVE-2026-66037?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-66037, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2026-66037

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