CVE catalog

CVE-2021-38492

firefox-esr: CVE-2021-38492

Severity: Medium · CVSS 6.1CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Published: Sep 22, 2021, 2:47:35 PM UTC
Source: [NVD] · [CVE record]
EPSS: 1.16% · Oct 25, 2026

When delegating navigations to the operating system, Firefox would accept the `mk` scheme which might allow attackers to launch pages and execute scripts in Internet Explorer in unprivileged mode. *This bug only affects Firefox for Windows. Other operating systems are unaffected.*. This vulnerability affects Firefox < 92, Thunderbird < 91.1, Thunderbird < 78.14, Firefox ESR < 78.14, and Firefox ESR < 91.1.

Vulnerable and fixed packages

Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.

Distribution	Package	Release	Version	Status
Debian	firefox-esr	sid	`153.5.1esr-1`	not affected
Debian	firefox-esr	forky	`153.5.1esr-1`	not affected
Debian	firefox-esr	trixie	`140.15.0esr-1~deb13u1`	not affected
Debian	firefox-esr	trixie-security	`153.5.1esr-1~deb13u1`	not affected
Debian	firefox-esr	bookworm	`140.12.0esr-1~deb12u1`	not affected
Debian	firefox-esr	bookworm-security	`153.5.1esr-1~deb12u1`	not affected
Debian	thunderbird	sid	`1:153.5.1esr-1`	not affected
Debian	thunderbird	forky	`1:153.5.0esr-1`	not affected
Debian	thunderbird	trixie	`1:140.12.0esr-1~deb13u1`	not affected
Debian	thunderbird	trixie-security	`1:153.5.1esr-1~deb13u2`	not affected
Debian	thunderbird	bookworm	`1:140.12.0esr-1~deb12u1`	not affected
Debian	thunderbird	bookworm-security	`1:153.5.1esr-1~deb12u1`	not affected
Ubuntu	mozjs52	18.04	`52.3.1-0ubuntu3`	vulnerable
Ubuntu	mozjs52	18.04	`52.3.1-7fakesync1`	vulnerable
Ubuntu	mozjs52	18.04	`52.8.1-0ubuntu0.18.04.1`	vulnerable
Ubuntu	mozjs52	18.04	`52.9.1-0ubuntu0.18.04.1`	vulnerable
Ubuntu	mozjs38	18.04	`38.8.0~repack1-0ubuntu1`	vulnerable
Ubuntu	mozjs38	18.04	`38.8.0~repack1-0ubuntu3`	vulnerable
Ubuntu	mozjs38	18.04	`38.8.0~repack1-0ubuntu4`	vulnerable
Ubuntu	mozjs68	20.04	`68.5.0-1~fakesync`	vulnerable
Ubuntu	mozjs68	20.04	`68.5.0-2~fakesync`	vulnerable
Ubuntu	mozjs68	20.04	`68.6.0-1`	vulnerable
Ubuntu	mozjs68	20.04	`68.6.0-1ubuntu1`	vulnerable
Ubuntu	mozjs52	20.04	`52.9.1-1build1`	vulnerable
Ubuntu	mozjs52	20.04	`52.9.1-1ubuntu3`	vulnerable
Ubuntu	mozjs78	22.04	`78.13.0-1`	vulnerable
Ubuntu	mozjs78	22.04	`78.15.0-2`	vulnerable
Ubuntu	mozjs78	22.04	`78.15.0-4ubuntu1`	vulnerable

Fixed-version evidence

Distribution	Package	Type	Release	Fixed version	Urgency	Origin	Bugs
Debian	firefox-esr	source	sid	`Not affected`	unimportant	Not reported	Not reported
Debian	firefox-esr	source	forky	`Not affected`	unimportant	Not reported	Not reported
Debian	firefox-esr	source	trixie	`Not affected`	unimportant	Not reported	Not reported
Debian	firefox-esr	source	bookworm	`Not affected`	unimportant	Not reported	Not reported
Debian	thunderbird	source	sid	`Not affected`	unimportant	Not reported	Not reported
Debian	thunderbird	source	forky	`Not affected`	unimportant	Not reported	Not reported
Debian	thunderbird	source	trixie	`Not affected`	unimportant	Not reported	Not reported
Debian	thunderbird	source	bookworm	`Not affected`	unimportant	Not reported	Not reported

OpenFactory catalog packages

Matching against OpenFactory catalog package versions is in progress.

[Debian 12 (Bookworm)]

[firefox-esr]Unknown
Details (4)
- 140.12.0esr-1~deb12u1 · amd64 · bookworm
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.12.0esr-1~deb12u1 · arm64 · bookworm
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.14.0esr-1~deb12u1 · amd64 · bookworm-security
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.14.0esr-1~deb12u1 · arm64 · bookworm-security
  Not affected
  dsa · firefox-esr · debian · bookworm
[firefox-esr-l10n-ach]Unknown
Source package: [firefox-esr]
Details (4)
- 140.12.0esr-1~deb12u1 · all · bookworm
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.12.0esr-1~deb12u1 · all · bookworm
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.14.0esr-1~deb12u1 · all · bookworm-security
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.14.0esr-1~deb12u1 · all · bookworm-security
  Not affected
  dsa · firefox-esr · debian · bookworm
[firefox-esr-l10n-af]Unknown
Source package: [firefox-esr]
Details (4)
- 140.12.0esr-1~deb12u1 · all · bookworm
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.12.0esr-1~deb12u1 · all · bookworm
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.14.0esr-1~deb12u1 · all · bookworm-security
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.14.0esr-1~deb12u1 · all · bookworm-security
  Not affected
  dsa · firefox-esr · debian · bookworm
[firefox-esr-l10n-all]Unknown
Source package: [firefox-esr]
Details (4)
- 140.12.0esr-1~deb12u1 · all · bookworm
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.12.0esr-1~deb12u1 · all · bookworm
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.14.0esr-1~deb12u1 · all · bookworm-security
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.14.0esr-1~deb12u1 · all · bookworm-security
  Not affected
  dsa · firefox-esr · debian · bookworm
[firefox-esr-l10n-an]Unknown
Source package: [firefox-esr]
Details (4)
- 140.12.0esr-1~deb12u1 · all · bookworm
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.12.0esr-1~deb12u1 · all · bookworm
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.14.0esr-1~deb12u1 · all · bookworm-security
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.14.0esr-1~deb12u1 · all · bookworm-security
  Not affected
  dsa · firefox-esr · debian · bookworm
[firefox-esr-l10n-ar]Unknown
Source package: [firefox-esr]
Details (4)
- 140.12.0esr-1~deb12u1 · all · bookworm
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.12.0esr-1~deb12u1 · all · bookworm
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.14.0esr-1~deb12u1 · all · bookworm-security
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.14.0esr-1~deb12u1 · all · bookworm-security
  Not affected
  dsa · firefox-esr · debian · bookworm
[firefox-esr-l10n-ast]Unknown
Source package: [firefox-esr]
Details (4)
- 140.12.0esr-1~deb12u1 · all · bookworm
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.12.0esr-1~deb12u1 · all · bookworm
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.14.0esr-1~deb12u1 · all · bookworm-security
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.14.0esr-1~deb12u1 · all · bookworm-security
  Not affected
  dsa · firefox-esr · debian · bookworm
[firefox-esr-l10n-az]Unknown
Source package: [firefox-esr]
Details (4)
- 140.12.0esr-1~deb12u1 · all · bookworm
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.12.0esr-1~deb12u1 · all · bookworm
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.14.0esr-1~deb12u1 · all · bookworm-security
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.14.0esr-1~deb12u1 · all · bookworm-security
  Not affected
  dsa · firefox-esr · debian · bookworm
[firefox-esr-l10n-be]Unknown
Source package: [firefox-esr]
Details (4)
- 140.12.0esr-1~deb12u1 · all · bookworm
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.12.0esr-1~deb12u1 · all · bookworm
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.14.0esr-1~deb12u1 · all · bookworm-security
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.14.0esr-1~deb12u1 · all · bookworm-security
  Not affected
  dsa · firefox-esr · debian · bookworm
[firefox-esr-l10n-bg]Unknown
Source package: [firefox-esr]
Details (4)
- 140.12.0esr-1~deb12u1 · all · bookworm
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.12.0esr-1~deb12u1 · all · bookworm
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.14.0esr-1~deb12u1 · all · bookworm-security
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.14.0esr-1~deb12u1 · all · bookworm-security
  Not affected
  dsa · firefox-esr · debian · bookworm
[firefox-esr-l10n-bn]Unknown
Source package: [firefox-esr]
Details (4)
- 140.12.0esr-1~deb12u1 · all · bookworm
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.12.0esr-1~deb12u1 · all · bookworm
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.14.0esr-1~deb12u1 · all · bookworm-security
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.14.0esr-1~deb12u1 · all · bookworm-security
  Not affected
  dsa · firefox-esr · debian · bookworm
[firefox-esr-l10n-br]Unknown
Source package: [firefox-esr]
Details (4)
- 140.12.0esr-1~deb12u1 · all · bookworm
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.12.0esr-1~deb12u1 · all · bookworm
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.14.0esr-1~deb12u1 · all · bookworm-security
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.14.0esr-1~deb12u1 · all · bookworm-security
  Not affected
  dsa · firefox-esr · debian · bookworm
[firefox-esr-l10n-bs]Unknown
Source package: [firefox-esr]
Details (4)
- 140.12.0esr-1~deb12u1 · all · bookworm
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.12.0esr-1~deb12u1 · all · bookworm
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.14.0esr-1~deb12u1 · all · bookworm-security
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.14.0esr-1~deb12u1 · all · bookworm-security
  Not affected
  dsa · firefox-esr · debian · bookworm
[firefox-esr-l10n-ca]Unknown
Source package: [firefox-esr]
Details (4)
- 140.12.0esr-1~deb12u1 · all · bookworm
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.12.0esr-1~deb12u1 · all · bookworm
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.14.0esr-1~deb12u1 · all · bookworm-security
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.14.0esr-1~deb12u1 · all · bookworm-security
  Not affected
  dsa · firefox-esr · debian · bookworm
[firefox-esr-l10n-cak]Unknown
Source package: [firefox-esr]
Details (4)
- 140.12.0esr-1~deb12u1 · all · bookworm
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.12.0esr-1~deb12u1 · all · bookworm
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.14.0esr-1~deb12u1 · all · bookworm-security
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.14.0esr-1~deb12u1 · all · bookworm-security
  Not affected
  dsa · firefox-esr · debian · bookworm
[firefox-esr-l10n-ca-valencia]Unknown
Source package: [firefox-esr]
Details (4)
- 140.12.0esr-1~deb12u1 · all · bookworm
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.12.0esr-1~deb12u1 · all · bookworm
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.14.0esr-1~deb12u1 · all · bookworm-security
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.14.0esr-1~deb12u1 · all · bookworm-security
  Not affected
  dsa · firefox-esr · debian · bookworm
[firefox-esr-l10n-cs]Unknown
Source package: [firefox-esr]
Details (4)
- 140.12.0esr-1~deb12u1 · all · bookworm
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.12.0esr-1~deb12u1 · all · bookworm
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.14.0esr-1~deb12u1 · all · bookworm-security
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.14.0esr-1~deb12u1 · all · bookworm-security
  Not affected
  dsa · firefox-esr · debian · bookworm
[firefox-esr-l10n-cy]Unknown
Source package: [firefox-esr]
Details (4)
- 140.12.0esr-1~deb12u1 · all · bookworm
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.12.0esr-1~deb12u1 · all · bookworm
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.14.0esr-1~deb12u1 · all · bookworm-security
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.14.0esr-1~deb12u1 · all · bookworm-security
  Not affected
  dsa · firefox-esr · debian · bookworm
[firefox-esr-l10n-da]Unknown
Source package: [firefox-esr]
Details (4)
- 140.12.0esr-1~deb12u1 · all · bookworm
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.12.0esr-1~deb12u1 · all · bookworm
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.14.0esr-1~deb12u1 · all · bookworm-security
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.14.0esr-1~deb12u1 · all · bookworm-security
  Not affected
  dsa · firefox-esr · debian · bookworm
[firefox-esr-l10n-de]Unknown
Source package: [firefox-esr]
Details (4)
- 140.12.0esr-1~deb12u1 · all · bookworm
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.12.0esr-1~deb12u1 · all · bookworm
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.14.0esr-1~deb12u1 · all · bookworm-security
  Not affected
  dsa · firefox-esr · debian · bookworm
- 140.14.0esr-1~deb12u1 · all · bookworm-security
  Not affected
  dsa · firefox-esr · debian · bookworm

Next results

Observed: Oct 23, 2026, 6:01:44 PM UTC

References

[Debian Security Tracker] · [FIRST EPSS] · [OSV Package Vulnerability Database] · [SUSE security advisories and VEX]