CVE-2020-26958 — Cross-site Scripting in Mozilla Firefox

CWE-79 — Cross-site Scripting12 documents8 sources
Severity
6.1MEDIUMNVD
EPSS
0.5%
top 35.85%
CISA KEV
Not in KEV
Exploit
No known exploits
Affected products
3
Mozilla FirefoxMozilla Firefox ESRMozilla Thunderbird
Timeline
PublishedDec 9
Latest updateMay 24

Description

Firefox did not block execution of scripts with incorrect MIME types when the response was intercepted and cached through a ServiceWorker. This could lead to a cross-site script inclusion vulnerability, or a Content Security Policy bypass. 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-3qgm-cw58-7h2p: Firefox did not block execution of scripts with incorrect MIME types when the response was intercepted and cached through a ServiceWorker↗2022-05-24
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OSV
CVE-2020-26958: Firefox did not block execution of scripts with incorrect MIME types when the response was intercepted and cached through a ServiceWorker↗2020-12-09
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CVEList
CVE-2020-26958: Firefox did not block execution of scripts with incorrect MIME types when the response was intercepted and cached through a ServiceWorker↗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: Requests intercepted through ServiceWorkers lacked MIME type restrictions↗2020-11-17
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Debian
CVE-2020-26958: firefox - Firefox did not block execution of scripts with incorrect MIME types when the re...↗2020
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CVE-2020-26958 — Cross-site Scripting in Mozilla | cvebase