CVE-2021-23997

high

Published — · Modified —

CVSS v3

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CVSS v2

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VIR risk

8.0

Description

Due to unexpected data type conversions, a use-after-free could have occurred when interacting with the font cache. We presume that with enough effort this could have been exploited to run arbitrary code. This vulnerability affects Firefox < 88.

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-2021-23997

vendor Authored 2026-05-27

Vendor advisory: suse — https://www.suse.com/security/cve/CVE-2021-23997.html

vendor Authored 2026-05-27

Vendor advisory: arch — https://security.archlinux.org/ASA-202104-3

OS impact

OS	Version	Status	Fixed in
arch		fixed	`88.0-1`
sles		affected
debian	sid	fixed	`88.0-1`

References

https://security.archlinux.org/ASA-202104-3
https://www.suse.com/security/cve/CVE-2021-23997.html
https://security-tracker.debian.org/tracker/CVE-2021-23997

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