CVE-2021-38505

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

Description

Microsoft introduced a new feature in Windows 10 known as Cloud Clipboard which, if enabled, will record data copied to the clipboard to the cloud, and make it available on other computers in certain scenarios. Applications that wish to prevent copied data from being recorded in Cloud History must use specific clipboard formats; and Firefox before versions 94 and ESR 91.3 did not implement them. This could have caused sensitive data to be recorded to a user's Microsoft account. *This bug only affects Firefox for Windows 10+ with Cloud Clipboard enabled. Other operating systems are unaffected.*. This vulnerability affects Firefox < 94, Thunderbird < 91.3, and Firefox ESR < 91.3.

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-2021-38505

vendor Authored 2026-05-27

Vendor advisory: suse — https://www.suse.com/security/cve/CVE-2021-38505.html

OS impact

OSVersionStatusFixed in
arch archfixed91.3.0-1
suse slesaffected
debian debiansidfixed0
debian debianbookwormfixed0
debian debianbullseyefixed0
debian debianforkyfixed0
debian debiantrixiefixed0

References

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