Cyber Resilience

CVE-2021-29985

HighPublic PoC

Published: 17 August 2021

Published
17 August 2021
Modified
21 November 2024
KEV Added
—
Patch
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CVSS Score v3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS Score 0.0041 61.8th percentile
Risk Priority 18 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-29985 is a high-severity Use After Free (CWE-416) vulnerability in Mozilla Firefox. Its CVSS base score is 8.8 (High).

Operationally, ranked in the top 38.2% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

EU & UK References

Vulnerability details

A use-after-free vulnerability in media channels could have led to memory corruption and a potentially exploitable crash. This vulnerability affects Thunderbird < 78.13, Thunderbird < 91, Firefox ESR < 78.13, and Firefox < 91.

CWE(s)
CWE-416

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

mozilla
firefox
≤ 91.0
mozilla
firefox esr
≤ 78.13.0
mozilla
thunderbird
≤ 78.13.0

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

SI-16 Memory Protection
addresses: CWE-416

Use-after-free exploits that achieve arbitrary code execution are blocked or significantly hardened by non-executable pages and ASLR.

References