CVE-2021-23953

MEDIUM

Firefox < 85 - Thunderbird < 78.7 - Firefox ESR < 78.7 - XSS

Title source: llm
STIX 2.1

Description

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.

References (4)

Core 4
Core References
Release Notes, Vendor Advisory x_refsource_misc
https://www.mozilla.org/security/advisories/mfsa2021-03/
Release Notes, Vendor Advisory x_refsource_misc
https://www.mozilla.org/security/advisories/mfsa2021-04/
Release Notes, Vendor Advisory x_refsource_misc
https://www.mozilla.org/security/advisories/mfsa2021-05/
Issue Tracking, Permissions Required, Vendor Advisory x_refsource_misc
https://bugzilla.mozilla.org/show_bug.cgi?id=1683940

Scores

CVSS v3 4.3
EPSS 0.0038
EPSS Percentile 59.5%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N

Details

Status published
Products (3)
mozilla/firefox < 85.0
mozilla/firefox_esr < 78.7
mozilla/thunderbird < 78.7
Published Feb 26, 2021
Tracked Since Feb 18, 2026