CVE-2026-53900

MEDIUM 4.3

Cookie injection was possible when opening a PDF link

CVSS Score

4.3

EPSS Score

0.0%

EPSS Percentile

0th

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.

Vendor	mozilla
Product	firefox for ios
Ecosystems	Browser JavaScript
Industries	Technology
Published	Jun 16, 2026
Last Updated	Jun 16, 2026

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Affected Versions

Mozilla / Firefox for iOS

All versions affected

References

NVD ↗ CVE.org ↗ EPSS Data ↗

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

Credits

Muneaki Nishimura