CVE-2026-53900 Cookie injection was possible when opening a PDF link

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...

CVE-2026-53900

CVE-2026-53900 concerns Firefox for iOS. The issue: cookies set on the initial PDF request were preserved across cross-origin HTTP redirects in TemporaryDocument, enabling a malicious site to inject cookies into requests to an unrelated target domain. The CVE has a base score of 4.3 (Medium) per ...