Medium severity6.5NVD Advisory· Published Dec 8, 2021· Updated Jun 17, 2026
CVE-2021-43542
CVE-2021-43542
Description
Using XMLHttpRequest, an attacker could have identified installed applications by probing error messages for loading external protocols. This vulnerability affects Thunderbird < 91.4.0, Firefox ESR < 91.4.0, and Firefox < 95.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected products
49<91.4.0+ 2 more
- (no CPE)range: <91.4.0
- (no CPE)range: unspecified
- cpe:2.3:a:mozilla:thunderbird:*:*:*:*:*:*:*:*range: <91.4.0
<91.4.0+ 4 more
- (no CPE)range: <91.4.0
- (no CPE)range: unspecified
- (no CPE)range: unspecified
- cpe:2.3:a:mozilla:firefox:*:*:*:*:*:*:*:*range: <95.0
- cpe:2.3:a:mozilla:firefox_esr:*:*:*:*:*:*:*:*range: <91.4.0
- osv-coords38 versionspkg:rpm/opensuse/MozillaThunderbird&distro=openSUSE%20Tumbleweedpkg:rpm/suse/MozillaFirefox&distro=SUSE%20Enterprise%20Storage%206pkg:rpm/suse/MozillaFirefox&distro=HPE%20Helion%20OpenStack%208pkg:rpm/suse/MozillaFirefox&distro=SUSE%20OpenStack%20Cloud%208pkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Module%20for%20Desktop%20Applications%2015%20SP2pkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Module%20for%20Desktop%20Applications%2015%20SP3pkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20High%20Performance%20Computing%2015%20SP1-ESPOSpkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Server%2015-LTSSpkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2015%20SP1pkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2012%20SP4pkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Software%20Development%20Kit%2012%20SP5pkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Server%2012%20SP3-LTSSpkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Server%2012%20SP3-BCLpkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Server%2012%20SP5pkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2012%20SP5pkg:rpm/suse/MozillaThunderbird&distro=SUSE%20Linux%20Enterprise%20Workstation%20Extension%2015%20SP2pkg:rpm/almalinux/firefoxpkg:rpm/almalinux/thunderbirdpkg:rpm/opensuse/firefox-esr&distro=openSUSE%20Tumbleweedpkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20High%20Performance%20Computing%2015-ESPOSpkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20High%20Performance%20Computing%2015%20SP1-LTSSpkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Server%2015%20SP1-BCLpkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Server%2015%20SP1-LTSSpkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2015pkg:rpm/suse/MozillaFirefox&distro=SUSE%20OpenStack%20Cloud%209pkg:rpm/suse/MozillaFirefox&distro=SUSE%20OpenStack%20Cloud%20Crowbar%208pkg:rpm/suse/MozillaFirefox&distro=SUSE%20OpenStack%20Cloud%20Crowbar%209pkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Server%20for%20SAP%20Applications%2012%20SP3pkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Server%2012%20SP4-LTSSpkg:rpm/suse/MozillaThunderbird&distro=SUSE%20Linux%20Enterprise%20Workstation%20Extension%2015%20SP3pkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Server%2011%20SP4-LTSSpkg:rpm/opensuse/MozillaThunderbird&distro=openSUSE%20Leap%2015.2pkg:rpm/opensuse/MozillaFirefox&distro=openSUSE%20Leap%2015.3pkg:rpm/opensuse/MozillaThunderbird&distro=openSUSE%20Leap%2015.3pkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20High%20Performance%20Computing%2015-LTSSpkg:rpm/suse/MozillaFirefox&distro=SUSE%20Linux%20Enterprise%20Server%2012%20SP2-BCLpkg:rpm/opensuse/MozillaFirefox&distro=openSUSE%20Leap%2015.2pkg:rpm/opensuse/MozillaFirefox&distro=openSUSE%20Tumbleweed
< 91.4.0-1.1+ 37 more
- (no CPE)range: < 91.4.0-1.1
- (no CPE)range: < 91.4.0-150.9.1
- (no CPE)range: < 91.4.0-112.83.1
- (no CPE)range: < 91.4.0-112.83.1
- (no CPE)range: < 91.4.0-152.9.1
- (no CPE)range: < 91.4.0-152.9.1
- (no CPE)range: < 91.4.0-150.9.1
- (no CPE)range: < 91.4.0-150.9.1
- (no CPE)range: < 91.4.0-150.9.1
- (no CPE)range: < 91.4.0-112.83.1
- (no CPE)range: < 91.4.0-112.83.1
- (no CPE)range: < 91.4.0-112.83.1
- (no CPE)range: < 91.4.0-112.83.1
- (no CPE)range: < 91.4.0-112.83.1
- (no CPE)range: < 91.4.0-112.83.1
- (no CPE)range: < 91.4.0-8.45.2
- (no CPE)range: < 91.4.0-1.el8_5.alma
- (no CPE)range: < 91.4.0-2.el8_5.alma
- (no CPE)range: < 128.5.1-1.1
- (no CPE)range: < 91.4.0-150.9.1
- (no CPE)range: < 91.4.0-150.9.1
- (no CPE)range: < 91.4.0-150.9.1
- (no CPE)range: < 91.4.0-150.9.1
- (no CPE)range: < 91.4.0-150.9.1
- (no CPE)range: < 91.4.0-112.83.1
- (no CPE)range: < 91.4.0-112.83.1
- (no CPE)range: < 91.4.0-112.83.1
- (no CPE)range: < 91.4.0-112.83.1
- (no CPE)range: < 91.4.0-112.83.1
- (no CPE)range: < 91.4.0-8.45.2
- (no CPE)range: < 91.4.0-78.154.1
- (no CPE)range: < 91.4.0-lp152.2.52.1
- (no CPE)range: < 91.4.0-152.9.1
- (no CPE)range: < 91.4.0-8.45.2
- (no CPE)range: < 91.4.0-150.9.1
- (no CPE)range: < 91.4.0-112.83.1
- (no CPE)range: < 91.4.0-lp152.2.74.1
- (no CPE)range: < 95.0-1.1
Patches
Vulnerability mechanics
References
10- bugzilla.mozilla.org/show_bug.cginvdIssue TrackingPermissions RequiredVendor Advisory
- lists.debian.org/debian-lts-announce/2021/12/msg00030.htmlnvdMailing ListThird Party Advisory
- lists.debian.org/debian-lts-announce/2022/01/msg00001.htmlnvdMailing ListThird Party Advisory
- security.gentoo.org/glsa/202202-03nvdThird Party Advisory
- security.gentoo.org/glsa/202208-14nvdThird Party Advisory
- www.debian.org/security/2021/dsa-5026nvdThird Party Advisory
- www.debian.org/security/2022/dsa-5034nvdThird Party Advisory
- www.mozilla.org/security/advisories/mfsa2021-52/nvdVendor Advisory
- www.mozilla.org/security/advisories/mfsa2021-53/nvdVendor Advisory
- www.mozilla.org/security/advisories/mfsa2021-54/nvdVendor Advisory
News mentions
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