CWE
209
Advisory Published
CVE Published
Updated

CVE-2021-43542

First published: Tue Dec 07 2021(Updated: )

Using XMLHttpRequest, an attacker could have identified installed applications by probing error messages for loading external protocols.

Credit: security@mozilla.org security@mozilla.org

Affected SoftwareAffected VersionHow to fix
Mozilla Thunderbird<91.4
91.4
debian/firefox
118.0.2-1
debian/firefox-esr
91.12.0esr-1~deb10u1
115.3.1esr-1~deb10u1
102.15.0esr-1~deb11u1
115.3.1esr-1~deb11u1
102.15.1esr-1~deb12u1
115.3.0esr-1~deb12u1
115.3.0esr-1
115.4.0esr-1
debian/thunderbird
1:91.12.0-1~deb10u1
1:115.3.1-1~deb10u1
1:102.13.1-1~deb11u1
1:115.3.1-1~deb11u1
1:102.15.1-1~deb12u1
1:115.3.1-1~deb12u1
1:115.3.1-1
Mozilla Firefox ESR<91.4
91.4
Mozilla Firefox<95
95
Mozilla Firefox<95.0
Mozilla Firefox ESR<91.4.0
Mozilla Thunderbird<91.4.0
Debian GNU/Linux=9.0
Debian GNU/Linux=10.0
Debian GNU/Linux=11.0

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Parent vulnerabilities

(Appears in the following advisories)

Frequently Asked Questions

  • What is the vulnerability ID of this vulnerability?

    The vulnerability ID is CVE-2021-43542.

  • Which software versions are affected by this vulnerability?

    This vulnerability affects Thunderbird < 91.4.0, Firefox ESR < 91.4.0, and Firefox < 95.

  • How can an attacker exploit this vulnerability?

    An attacker can exploit this vulnerability by using XMLHttpRequest to probe error messages for loading external protocols, allowing them to identify installed applications.

  • What is the severity level of this vulnerability?

    This vulnerability has a severity level of medium.

  • Where can I find more information about this vulnerability?

    You can find more information about this vulnerability at the following references: [link1](https://bugzilla.mozilla.org/show_bug.cgi?id=1723281), [link2](https://www.mozilla.org/en-US/security/advisories/mfsa2021-54/), [link3](https://www.mozilla.org/en-US/security/advisories/mfsa2021-52/).

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