Home/CVE/Firefox did not block execution of scripts with incorrect MIME types when the response was intercepted and cached throug
CVE

CVE-2020-26958

Firefox did not block execution of scripts with incorrect MIME types when the response was intercepted and cached throug

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.

MEDIUM · CVSS 6.1 EPSS 0.00661
Monitor
  • No active-exploitation, high-EPSS, or public-exploit signals - routine patching cadence
Sigma rules1 YARA rules0
⬡

Weakness Classification

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
▤

Affected Products & Versions

3
mozilla firefox< 83.0
mozilla firefox esr< 78.5
mozilla thunderbird< 78.5
◈

Sigma Hunt Rules

1
Exact rules name this CVE ID. Product rules name an affected product in their title. Related rules cover techniques used by actors who exploited this CVE. Showing the most relevant matches; the complete related set is on the full drill-down.
producthighSQLite Firefox Profile Data DB Access
▣

Scoring & Timeline

6.1
MEDIUM · CVSS v3.1 · security@mozilla.org
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD09 Dec 2020 · 01:15 AM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
⚑

Vendor Advisories

29
suse-csafopenSUSE-SU-2024:14572-1
suse-csafopenSUSE-SU-2024:10600-1
suse-csafopenSUSE-SU-2024:10601-1
suse-csafopenSUSE-SU-2020:2315-1
suse-csafopenSUSE-SU-2020:2187-1
🔗

References & Sources

4
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://bugzilla.mozilla.org/show_bug.cgi?id=1669355Issue TrackingPermissions RequiredVendor Advisory
https://www.mozilla.org/security/advisories/mfsa2020-50/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2020-51/Vendor Advisory
https://www.mozilla.org/security/advisories/mfsa2020-52/Vendor Advisory
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