CVE-2022-34476 — ASN

ASN.1 parsing of an indefinite SEQUENCE inside an indefinite GROUP could have resulted in the parser accepting malformed ASN.1. This vulnerability affects Firefox < 102.

01What is this vulnerability?

ASN.1 parsing of an indefinite SEQUENCE inside an indefinite GROUP could have resulted in the parser accepting malformed ASN.1. This vulnerability affects Firefox < 102.

02Affected products

Vendor	Product	Versions
Mozilla	Firefox	unspecified

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: 2022-12-22T00:00:00.000Z
• Last modified: 2025-04-15T18:26:49.845Z

09References

• www.mozilla.org — https://www.mozilla.org/security/advisories/mfsa2022-24/
• bugzilla.mozilla.org — https://bugzilla.mozilla.org/show_bug.cgi?id=1387919