CVE-2026-53900
Undergoing Analysis Undergoing Analysis - In Progress

Firefox for iOS Cookie Injection via Cross-Origin PDF Redirect

Publication date: 2026-06-16

Last updated on: 2026-06-16

Assigner: Mozilla Corporation

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.

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Meta Information

Published
2026-06-16
Last Modified
2026-06-16
Generated
2026-07-06
AI Q&A
2026-06-16
EPSS Evaluated
2026-07-05
NVD
CVE-2026-53900
EUVD
EUVD-2026-37078

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
mozilla firefox_for_ios 152.0

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-384 Authenticating a user, or otherwise establishing a new user session, without invalidating any existing session identifier gives an attacker the opportunity to steal authenticated sessions.
CWE-345 The product does not sufficiently verify the origin or authenticity of data, in a way that causes it to accept invalid data.

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Compliance Impact

The vulnerability allows a malicious site to inject arbitrary cookies into requests to unrelated target domains, potentially exposing sensitive user session data across domains.

Such exposure of sensitive data could lead to non-compliance with data protection regulations like GDPR and HIPAA, which require strict controls on personal and sensitive information to prevent unauthorized access or leakage.

Executive Summary

This vulnerability in Firefox for iOS involved the browser preserving cookies set on the initial PDF request across cross-origin HTTP redirects within TemporaryDocument. This behavior allowed a malicious website to inject arbitrary cookies into requests sent to an unrelated target domain.

The issue was fixed in Firefox for iOS version 152.0.

Impact Analysis

An attacker could exploit this vulnerability to inject arbitrary cookies into requests to unrelated domains. This could lead to unauthorized actions or access if the injected cookies are used for authentication or session management by the target domain.

Mitigation Strategies

To mitigate this vulnerability, update Firefox for iOS to version 152.0 or later, where the issue has been fixed.

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