CVE-2026-53900

Cookie injection was possible when opening a PDF link

State: Published
Severity: 4.3 Medium
Published: Jun 16, 2026
Updated: Jun 16, 2026
Reserved: Jun 11, 2026

Description

Firefox for iOS preserved cookies set on the initial PDF request across cross-origin HTTP redirects in TemporaryDocument, allowing a malicious site to inject arbitrary cookies into requests to an unrelated target domain. This vulnerability was fixed in Firefox for iOS 152.0.

Scores

CVSS	Score	Vector	Source
3.1	4.3 Medium	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N	CISA-ADP

Weaknesses

CWE-345 Insufficient Verification of Data Authenticity
CWE-384 Session Fixation

Affected Products

Product	Versions
Firefox for iOSMozilla	152.0 and laterNot affected

References

https://bugzilla.mozilla.org/show_bug.cgi?id=2043204
https://www.mozilla.org/security/advisories/mfsa2026-56/

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