CVE-2020-12391

critical

Published — · Modified —

CVSS v3

—

CVSS v2

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VIR risk

9.5

Description

Documents formed using data: URLs in an OBJECT element failed to inherit the CSP of the creating context. This allowed the execution of scripts that should have been blocked, albeit with a unique opaque origin. This vulnerability affects Firefox < 76.

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-2020-12391

vendor Authored 2026-05-27

Vendor advisory: arch — https://security.archlinux.org/ASA-202005-3

OS impact

OS	Version	Status	Fixed in
arch		fixed	`76.0-1`
debian	sid	fixed	`76.0-1`

References

https://security.archlinux.org/ASA-202005-3
https://security-tracker.debian.org/tracker/CVE-2020-12391

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