CVE-2021-29987

high
Published — · Modified —
CVSS v3
CVSS v2
VIR risk
8.0

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.

Predictions

Exploit likelihood
20%
Patch ETA

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

vendor Authored 2026-05-27

Vendor advisory: debian — https://security-tracker.debian.org/tracker/CVE-2021-29987

vendor Authored 2026-05-27

Vendor advisory: arch — https://security.archlinux.org/ASA-202108-14

OS impact

OSVersionStatusFixed in
arch archfixed91.1.0-1
debian debiansidfixed91.0-1
debian debianbookwormfixed0
debian debianbullseyefixed0
debian debianforkyfixed0
debian debiantrixiefixed0

References

Verify integrity in audit chain (admin only). AS-IS.