CVE-2021-23969
Medium
Description
As specified in the W3C Content Security Policy draft, when creating a violation report, "User agents need to ensure that the source file is the URL requested by the page, pre-redirects. If that’s not possible, user agents need to strip the URL down to an origin to avoid unintentional leakage." Under certain types of redirects, Firefox incorrectly set the source file to be the destination of the redirects. This was fixed to be the redirect destination's origin. This vulnerability affects Firefox < 86, Thunderbird < 78.8, and Firefox ESR < 78.8.
SeverityMedium
CVSS4.3
Exploit probability—
Product
Mozilla Firefox
PublishedFeb 26, 2021
First seenFeb 26, 2021
How to fix
Update
- mozilla firefox86.0 or later
- mozilla firefox_esr78.8 or later
- mozilla thunderbird78.8 or later
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| mozilla firefox | v < 86.0 | 86.0 |
| mozilla firefox_esr | v < 78.8 | 78.8 |
| mozilla thunderbird | v < 78.8 | 78.8 |
| debian debian_linux | 9.0, 10.0 | — |
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