CVE-2020-26956 — Cross-site Scripting in Mozilla Firefox

CWE-79 — Cross-site Scripting12 documents8 sources
Severity
6.1MEDIUMNVD
EPSS
0.4%
top 37.24%
CISA KEV
Not in KEV
Exploit
No known exploits
Affected products
3
Mozilla FirefoxMozilla Firefox ESRMozilla Thunderbird
Timeline
PublishedDec 9
Latest updateMay 24

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.

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:NExploitability: 2.8 | Impact: 2.7

Affected Packages7 packages

▶CVEListV5mozilla/firefox< 83
▶NVDmozilla/firefox< 83.0
▶CVEListV5mozilla/firefox_esr< 78.5
▶CVEListV5mozilla/thunderbird< 78.5

🔴Vulnerability Details

3
GHSA
GHSA-2rfm-q54c-ww9j: In some cases, removing HTML elements during sanitization would keep existing SVG event handlers and therefore lead to XSS↗2022-05-24
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OSV
CVE-2020-26956: In some cases, removing HTML elements during sanitization would keep existing SVG event handlers and therefore lead to XSS↗2020-12-09
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CVEList
CVE-2020-26956: In some cases, removing HTML elements during sanitization would keep existing SVG event handlers and therefore lead to XSS↗2020-12-09
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📋Vendor Advisories

8
Ubuntu
Thunderbird vulnerabilities↗2020-11-25
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Ubuntu
Firefox vulnerabilities↗2020-11-19
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Ubuntu
Firefox vulnerabilities↗2020-11-18
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Red Hat
Mozilla: XSS through paste (manual and clipboard API)↗2020-11-17
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Debian
CVE-2020-26956: firefox - In some cases, removing HTML elements during sanitization would keep existing SV...↗2020
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CVE-2020-26956 — Cross-site Scripting in Mozilla | cvebase