CVE-2026-53900

Cookie injection was possible when opening a PDF link

Medium · published June 16, 2026

CVSS v3.1
4.3
EPSS
0%
Percentile
3.4
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v3.1
4.3 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:N/A:N
CVSS v4.0
Not supplied
EPSS
0.00144 · 3.4th percentile
Published
2026-06-16T11:53Z
EPSS history
Timeline
  • 16 JUN 11:53Z
    Cookie injection was possible when opening a PDF link
    cvelistv5