Vulnerability · Published Jun 16, 2026 · Assigned by mozilla
CVE-2026-53900Cookie injection was possible when opening a PDF link
Medium 4.3
In plain English
A medium-severity insufficient verification of data authenticity in Firefox for iOS from Mozilla. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.1% (higher than 1% of all known vulnerabilities).
Severity (CVSS 3.1)4.3Medium
Exploit odds (30 days)0.1%top 99.2% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official 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.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Mozilla | Firefox for iOS | see references |
Weakness: CWE-345, CWE-384 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N