CVE-2019-9717 — In Libav 12

In Libav 12.3, a denial of service in the subtitle decoder allows attackers to hog the CPU via a crafted video file in Matroska format, because srt_to_ass in libavcodec/srtdec.c has a complex format argument to sscanf.

01What is this vulnerability?

In Libav 12.3, a denial of service in the subtitle decoder allows attackers to hog the CPU via a crafted video file in Matroska format, because srt_to_ass in libavcodec/srtdec.c has a complex format argument to sscanf.

02Affected products

Vendor	Product	Versions
n	a / n/a	n/a

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2019-09-19T20:28:19.000Z
• Last modified: 2024-08-04T22:01:53.259Z

09References

• github.com — https://github.com/libav/libav/blob/df744e3cf66548c9167ea857104a29d2ea92819e/lib…
• lgtm.com — https://lgtm.com/security/