CVE-2021-43541

When invoking protocol handlers for external protocols, a supplied parameter URL containing spaces was not properly escaped. This vulnerability affects Thunderbird < 91.4.0, Firefox ESR < 91.4.0, and Firefox < 95.

• https://bugzilla.mozilla.org/show_bug.cgi?id=1696685Issue Tracking, Permissions Required, Vendor Advisory
• https://lists.debian.org/debian-lts-announce/2021/12/msg00030.htmlMailing List, Third Party Advisory
• https://lists.debian.org/debian-lts-announce/2022/01/msg00001.htmlMailing List, Third Party Advisory
• https://security.gentoo.org/glsa/202202-03Third Party Advisory
• https://security.gentoo.org/glsa/202208-14Third Party Advisory
• https://www.debian.org/security/2021/dsa-5026Third Party Advisory
• https://www.debian.org/security/2022/dsa-5034Third Party Advisory
• https://www.mozilla.org/security/advisories/mfsa2021-52/Vendor Advisory
• https://www.mozilla.org/security/advisories/mfsa2021-53/Vendor Advisory
• https://www.mozilla.org/security/advisories/mfsa2021-54/Vendor Advisory
• https://bugzilla.mozilla.org/show_bug.cgi?id=1696685Issue Tracking, Permissions Required, Vendor Advisory
• https://lists.debian.org/debian-lts-announce/2021/12/msg00030.htmlMailing List, Third Party Advisory
• https://lists.debian.org/debian-lts-announce/2022/01/msg00001.htmlMailing List, Third Party Advisory
• https://security.gentoo.org/glsa/202202-03Third Party Advisory
• https://security.gentoo.org/glsa/202208-14Third Party Advisory
• https://www.debian.org/security/2021/dsa-5026Third Party Advisory
• https://www.debian.org/security/2022/dsa-5034Third Party Advisory
• https://www.mozilla.org/security/advisories/mfsa2021-52/Vendor Advisory
• https://www.mozilla.org/security/advisories/mfsa2021-53/Vendor Advisory
• https://www.mozilla.org/security/advisories/mfsa2021-54/Vendor Advisory

Published

Dec 8, 2021

Last Modified

Jun 17, 2026

Status

Modified

• How Strix found a critical auth bypass in etcdStrix autonomously discovered a critical authentication bypass in etcd, later designated CVE-2026-33413.
• Autonomous PentestingAI agents that find and validate exploitable vulnerabilities like this one across your applications.
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