CVE-2021-23968
This could be used to leak sensitive information contained in such URIs.
Does this matter?
Lower severity and a low EPSS score (1.31%). Track it; it rarely justifies an emergency change on its own.
Description
If Content Security Policy blocked frame navigation, the full destination of a redirect served in the frame was reported in the violation report; as opposed to the original frame URI. This could be used to leak sensitive information contained in such URIs. This vulnerability affects Firefox < 86, Thunderbird < 78.8, and Firefox ESR < 78.8.
- CVSS 3.1
- 4.3 MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N
- EPSS
- 1.31% probability · 70th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-209
- Affected
- mozilla/firefox · mozilla/firefox esr · mozilla/thunderbird · debian/debian linux
- Source
- security@mozilla.org
EPSS 1.3% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://bugzilla.mozilla.org/show_bug.cgi?id=1687342Issue Tracking, Permissions Required, Vendor Advisory
- https://lists.debian.org/debian-lts-announce/2021/03/msg00000.htmlMailing List, Third Party Advisory
- https://security.gentoo.org/glsa/202104-09Third Party Advisory
- https://security.gentoo.org/glsa/202104-10Third Party Advisory
- https://www.debian.org/security/2021/dsa-4866Third Party Advisory
- https://www.mozilla.org/security/advisories/mfsa2021-07/Release Notes, Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2021-08/Release Notes, Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2021-09/Release Notes, Vendor Advisory
- https://bugzilla.mozilla.org/show_bug.cgi?id=1687342Issue Tracking, Permissions Required, Vendor Advisory
- https://lists.debian.org/debian-lts-announce/2021/03/msg00000.htmlMailing List, Third Party Advisory
- https://security.gentoo.org/glsa/202104-09Third Party Advisory
- https://security.gentoo.org/glsa/202104-10Third Party Advisory
- https://www.debian.org/security/2021/dsa-4866Third Party Advisory
- https://www.mozilla.org/security/advisories/mfsa2021-07/Release Notes, Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2021-08/Release Notes, Vendor Advisory
- https://www.mozilla.org/security/advisories/mfsa2021-09/Release Notes, Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.