CVE-2021-38509

MEDIUM

Firefox < 94, Thunderbird < 91.3, Firefox ESR < 91.3 - XSS

Title source: llm
STIX 2.1

Description

Due to an unusual sequence of attacker-controlled events, a Javascript alert() dialog with arbitrary (although unstyled) contents could be displayed over top an uncontrolled webpage of the attacker's choosing. This vulnerability affects Firefox < 94, Thunderbird < 91.3, and Firefox ESR < 91.3.

References (10)

Core 10
Core References
Issue Tracking, Permissions Required, Vendor Advisory x_refsource_misc
https://bugzilla.mozilla.org/show_bug.cgi?id=1718571
Third Party Advisory vendor-advisory x_refsource_debian
https://www.debian.org/security/2021/dsa-5026
Mailing List, Third Party Advisory mailing-list x_refsource_mlist
https://lists.debian.org/debian-lts-announce/2021/12/msg00030.html
Mailing List, Third Party Advisory vendor-advisory x_refsource_debian
https://www.debian.org/security/2022/dsa-5034
Mailing List, Third Party Advisory mailing-list x_refsource_mlist
https://lists.debian.org/debian-lts-announce/2022/01/msg00001.html
Third Party Advisory vendor-advisory x_refsource_gentoo
https://security.gentoo.org/glsa/202202-03
Third Party Advisory vendor-advisory x_refsource_gentoo
https://security.gentoo.org/glsa/202208-14

Scores

CVSS v3 4.3
EPSS 0.0163
EPSS Percentile 73.0%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N

Details

CWE
CWE-1021
Status published
Products (6)
debian/debian_linux 9.0
debian/debian_linux 10.0
debian/debian_linux 11.0
mozilla/firefox < 94.0
mozilla/firefox_esr < 91.3.0
mozilla/thunderbird < 91.3.0
Published Dec 08, 2021
Tracked Since Feb 18, 2026