CVE-2021-23986

high
Published — · Modified —
CVSS v3
CVSS v4 NEW
not yet in upstream
VIR risk
8.0

Description

A malicious extension with the 'search' permission could have installed a new search engine whose favicon referenced a cross-origin URL. The response to this cross-origin request could have been read by the extension, allowing a same-origin policy bypass by the extension, which should not have cross-origin permissions. This cross-origin request was made without cookies, so the sensitive information disclosed by the violation was limited to local-network resources or resources that perform IP-based authentication. This vulnerability affects Firefox < 87.

Predictions

Exploit likelihood
20%
Patch ETA

Heuristic predictions, AS-IS, for prioritization only.

Mitigations

No mitigations published for this CVE yet.

The vendor-content worker queues fetches as references arrive (check back in a few minutes). Or — if you've already worked around this in production — publish your fix to the community-verified tier.

✚ Propose a mitigation on Community → Mitigations published via the community go through AI scoring + 2 human reviewers + 7-day silent objection window before landing here with source_tier=community-verified.

OS impact

suse SUSE Affected 1 release
VersionStatusFixed in
Affected
arch Arch Fixed 1 release
VersionStatusFixed in
Fixed 87.0-1
debian Debian Fixed 1 release
VersionStatusFixed in
sid Fixed 87.0-1

References

Community-verified mitigations for this CVE will appear above when contributors publish them.

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