CVE-2020-26958: XSS
First published: Tue Nov 17 2020(Updated: )
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.
Credit: security@mozilla.org
| Affected Software | Affected Version | How to fix |
|---|---|---|
| Mozilla Firefox ESR | <78.5 | 78.5 |
| <83 | 83 | |
| <78.5 | 78.5 | |
| <78.5 | 78.5 | |
| Mozilla Firefox | <83.0 | |
| Mozilla Firefox ESR | <78.5 | |
| Mozilla Thunderbird | <78.5 |
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Reference Links
- https://bugzilla.mozilla.org/show_bug.cgi?id=1669355
- https://www.mozilla.org/en-US/security/advisories/mfsa2020-51/
- https://www.mozilla.org/en-US/security/advisories/mfsa2020-50/
- https://www.mozilla.org/en-US/security/advisories/mfsa2020-52/
- https://www.mozilla.org/security/advisories/mfsa2020-50/
- https://www.mozilla.org/security/advisories/mfsa2020-51/
- https://www.mozilla.org/security/advisories/mfsa2020-52/
Peer vulnerabilities
(Found alongside the following vulnerabilities)
Frequently Asked Questions
What is the vulnerability ID of this issue?
The vulnerability ID of this issue is CVE-2020-26958.
What is the severity of CVE-2020-26958?
The severity of CVE-2020-26958 is medium (4 on a scale of 1-10).
Which software is affected by CVE-2020-26958?
The software affected by CVE-2020-26958 includes Mozilla Firefox ESR version up to 78.5, Mozilla Firefox version up to 83, and Mozilla Thunderbird up to version 78.5.
What is the possible impact of CVE-2020-26958?
CVE-2020-26958 could lead to a cross-site script inclusion vulnerability or a Content Security Policy bypass.
How can I fix CVE-2020-26958?
To fix CVE-2020-26958, update Mozilla Firefox ESR to version 78.5 or later, update Mozilla Firefox to version 83 or later, and update Mozilla Thunderbird to version 78.5 or later.
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