Vulnerability in Mozilla Firefox
CVE-2021-23953
If a user clicked into a specifically crafted PDF, the PDF reader could be confused into leaking cross-origin information, when said information is served as chunked data. This vulnerability affects Firefox < 85, Thunderbird < 78.7, and Firefox ESR < 78.7.
EPSS: 0.010 (60.7th percentile) — read the EPSS interpretation.
CVSS v3 metric
CVSS v3 base score 4.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N.
Affected products
- Mozilla Firefox — versions < 85
- Mozilla Firefox Esr — versions < 78.7
- Mozilla Firefox_esr
- Mozilla Thunderbird — versions < 78.7
Public proof-of-concept exploits
References
- security@mozilla.org (x_refsource_MISC, Release Notes, Vendor Advisory)
- security@mozilla.org (x_refsource_MISC, Release Notes, Vendor Advisory)
- security@mozilla.org (x_refsource_MISC, Release Notes, Vendor Advisory)
- security@mozilla.org (Permissions Required, x_refsource_MISC, Issue Tracking, Vendor Advisory)
Frequently asked questions
- What is CVE-2021-23953?
- CVE-2021-23953 is a medium-severity vulnerability in Mozilla Firefox. CVSS score: 4.3/10. Published 2021-02-26.
- How severe is CVE-2021-23953?
- Medium severity. CVSS v3 base score is 4.3 out of 10.
- Is CVE-2021-23953 known to be exploited?
- 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.