CVE-2020-26958

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.

Category

6.1
CVSS
Severity: Medium
CVSS 3.1 •
CVSS 2.0 •
EPSS 0.30%
Vendor Advisory mozilla.org Vendor Advisory mozilla.org Vendor Advisory mozilla.org Vendor Advisory mozilla.org
Affected: Mozilla Firefox
Affected: Mozilla Firefox ESR
Affected: Mozilla Thunderbird
Published at:
Updated at:

References

Link Tags
https://bugzilla.mozilla.org/show_bug.cgi?id=1669355 vendor advisory issue tracking permissions required
https://www.mozilla.org/security/advisories/mfsa2020-50/ vendor advisory
https://www.mozilla.org/security/advisories/mfsa2020-52/ vendor advisory
https://www.mozilla.org/security/advisories/mfsa2020-51/ vendor advisory

Frequently Asked Questions

What is the severity of CVE-2020-26958?
CVE-2020-26958 has been scored as a medium severity vulnerability.
How to fix CVE-2020-26958?
To fix CVE-2020-26958, make sure you are using an up-to-date version of the affected component(s) by checking the vendor release notes. As for now, there are no other specific guidelines available.
Is CVE-2020-26958 being actively exploited in the wild?
As for now, there are no information to confirm that CVE-2020-26958 is being actively exploited. According to its EPSS score, there is a ~0% probability that this vulnerability will be exploited by malicious actors in the next 30 days.
What software or system is affected by CVE-2020-26958?
CVE-2020-26958 affects Mozilla Firefox, Mozilla Firefox ESR, Mozilla Thunderbird.
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