CVE-2021-38492
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.
Does this matter?
Lower severity and a low EPSS score (1.16%). Track it; it rarely justifies an emergency change on its own.
Description
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.
- CVSS 3.1
- 6.5 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N
- EPSS
- 1.16% probability · 65th percentile
- CISA KEV
- Not listed
- Affected
- mozilla/firefox · mozilla/firefox esr · mozilla/thunderbird
- Source
- security@mozilla.org
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=1721107Exploit, Issue Tracking, Vendor Advisory
- https://security.gentoo.org/glsa/202208-14Third Party Advisory
- https://www.mozilla.org/security/advisories/mfsa2021-38/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2021-39/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2021-40/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2021-41/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2021-42/Vendor Advisory
- https://bugzilla.mozilla.org/show_bug.cgi?id=1721107Exploit, Issue Tracking, Vendor Advisory
- https://security.gentoo.org/glsa/202208-14Third Party Advisory
- https://www.mozilla.org/security/advisories/mfsa2021-38/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2021-39/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2021-40/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2021-41/Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2021-42/Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.