CVE-2022-28281

HIGH EXPLOITED

Firefox < 99.0 and Firefox ESR < 91.8 - Out-of-bounds Write via WebAuthN Extensions

Title source: llm
STIX 2.1

Exploitation Summary

CVE-2022-28281 has been observed exploited in the wild (reported by VulnCheck KEV). EIP tracks 1 public exploit from researchers including 0vercl0k.

AI-analyzed exploit summary This PoC demonstrates an out-of-bounds write vulnerability in Mozilla Firefox (CVE-2022-28281) triggered by sending an unexpected number of WebAuthN Extensions in a `Register` command from a compromised renderer process. The exploit leads to memory corruption and a potentially exploitable crash.

Description

If a compromised content process sent an unexpected number of WebAuthN Extensions in a Register command to the parent process, an out of bounds write would have occurred leading to memory corruption and a potentially exploitable crash. This vulnerability affects Thunderbird < 91.8, Firefox < 99, and Firefox ESR < 91.8.

Exploits (1)

nomisec WORKING POC 74 stars
by 0vercl0k · client-side
https://github.com/0vercl0k/CVE-2022-28281

This PoC demonstrates an out-of-bounds write vulnerability in Mozilla Firefox (CVE-2022-28281) triggered by sending an unexpected number of WebAuthN Extensions in a `Register` command from a compromised renderer process. The exploit leads to memory corruption and a potentially exploitable crash.

Classification
Working Poc 100%
Attack Type
Rce
Complexity
Moderate
Reliability
Reliable
Target: Mozilla Firefox < 99
No auth needed
Prerequisites: Compromised Firefox renderer process · Windows OS
devstral-2 · analyzed Feb 16, 2026 Full analysis →

References (4)

Core 4

Scores

CVSS v3 8.8
EPSS 0.0258
EPSS Percentile 83.1%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

CISA SSVC

Vulnrichment
Exploitation none
Automatable no
Technical Impact total

Details

VulnCheck KEV 2022-08-15
CWE
CWE-787
Status published
Products (3)
mozilla/firefox < 99.0
mozilla/firefox_esr < 91.8
mozilla/thunderbird < 91.8
Published Dec 22, 2022
Tracked Since Feb 18, 2026