CVE-2021-23969
4.3
MEDIUM
CVSS 3.1
EPSS 1.2%
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.
How to fix CVE-2021-23969
To remediate CVE-2021-23969, upgrade the affected package to a fixed version below.
- —upgrade to 78.8.0esr-1 or later
- —upgrade to 1:78.8.0-1 or later
Is CVE-2021-23969 being exploited?
Low — EPSS is 1.2%, meaning exploitation activity has not been observed at scale.
Affected packages (2)
- from 0, < 78.8.0esr-1
- from 0, < 1:78.8.0-1
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | MEDIUM4.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N |