CVE-2020-26956

MEDIUM

Firefox <83 - Firefox ESR <78.5 - Thunderbird <78.5 - XSS

Title source: llm
STIX 2.1

Description

In some cases, removing HTML elements during sanitization would keep existing SVG event handlers and therefore lead to XSS. This vulnerability affects Firefox < 83, Firefox ESR < 78.5, and Thunderbird < 78.5.

References (4)

Core 4
Core References
Issue Tracking, Permissions Required, Vendor Advisory x_refsource_misc
https://bugzilla.mozilla.org/show_bug.cgi?id=1666300
Vendor Advisory x_refsource_confirm
https://www.mozilla.org/security/advisories/mfsa2020-50/
Vendor Advisory x_refsource_confirm
https://www.mozilla.org/security/advisories/mfsa2020-52/
Vendor Advisory x_refsource_confirm
https://www.mozilla.org/security/advisories/mfsa2020-51/

Scores

CVSS v3 6.1
EPSS 0.0033
EPSS Percentile 56.1%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Details

CWE
CWE-79
Status published
Products (3)
mozilla/firefox < 83.0
mozilla/firefox_esr < 78.5
mozilla/thunderbird < 78.5
Published Dec 09, 2020
Tracked Since Feb 18, 2026