CVE-2020-26958
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Insights vulnerability analysis
Description
The CVE Program describes this issue as:
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.
Additional information
- Bugzilla 1898735: Mozilla: Requests intercepted through ServiceWorkers lacked MIME type restrictions
- CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
- FAQ: Frequently asked questions about CVE-2020-26958
Common Vulnerability Scoring System (CVSS) Score Details
Important note
CVSS scores for open source components depend on vendor-specific factors (e.g. version or build chain). Therefore, Red Hat's score and impact rating can be different from NVD and other vendors. Red Hat remains the authoritative CVE Naming Authority (CNA) source for its products and services (see Red Hat classifications).
| Red Hat | NVD | |
|---|---|---|
CVSS v3 Base Score | 6.1 | 6.1 |
Attack Vector | Network | Network |
Attack Complexity | Low | Low |
Privileges Required | None | None |
User Interaction | Required | Required |
Scope | Changed | Changed |
Confidentiality Impact | Low | Low |
Integrity Impact | Low | Low |
Availability Impact | None | None |
CVSS v3 Vector
Red Hat: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
NVD: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Acknowledgements
Red Hat would like to thank the Mozilla project for reporting this issue. Upstream acknowledges Moti Harmats as the original reporter.
Frequently Asked Questions
Why is Red Hat's CVSS v3 score or Impact different from other vendors?
My product is listed as "Under investigation" or "Affected", when will Red Hat release a fix for this vulnerability?
What can I do if my product is listed as "Will not fix"?
What can I do if my product is listed as "Fix deferred"?
What is a mitigation?
I have a Red Hat product but it is not in the above list, is it affected?
Why is my security scanner reporting my product as vulnerable to this vulnerability even though my product version is fixed or not affected?
My product is listed as "Out of Support Scope". What does this mean?
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