CVE-2021-29987: mozilla firefox
Vulnerability summary
CVE-2021-29987 is a medium (CVSS 6.5) vulnerability in mozilla firefox. EPSS estimates a 0.95% chance of exploitation in the next 30 days, higher than 60.4% of scored vulnerabilities.
Advisory lineage
Upstream 0 · Downstream 17 · Related 17Timeline
- 17-08-2021PublishedVulnerability first disclosed.
- 03-08-2024Last modifiedVulnerability information updated.
Description
After requesting multiple permissions, and closing the first permission panel, subsequent permission panels will be displayed in a different position but still record a click in the default location, making it possible to trick a user into accepting a permission they did not want to. *This bug only affects Firefox on Linux. Other operating systems are unaffected.*. This vulnerability affects Firefox < 91 and Thunderbird < 91.
CVSS metrics
3 scores · 2 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated6.5MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
EPSS trend
Probability
0.95%
Chance of exploitation in the next 30 days
Percentile
60%
Versus all other CVEs
30-day change
0.00 pp
From 0.95% on 19-09-2026
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Ubuntu6 products
- firefox< 91.0+build2-0ubuntu0.18.04.1 | < 91.0+build2-0ubuntu0.20.04.1
- mozjs38All versions (No fix recorded)
- mozjs52All versions (No fix recorded)
- mozjs68All versions (No fix recorded)
- mozjs78All versions (No fix recorded)
Mozilla2 products
- firefox≥ unspecified, < 91 | < 91.0
- thunderbird≥ unspecified, < 91 | < 91.0
2 vendors · 8 products