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TI-2025-05835 Aliases CVE-2025-6434GHSA-87mm-rg9r-h8wm

HTTPS-Only exception screen lacked anti-clickjacking delay

Priority LOW 20CWE-1021Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Required
Attack complexity
Low
Impact type
Spoofing
Confidentiality · integrity · availability
None · Low · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA. Impact type from CWE-1021.

Summary

The exception page for the HTTPS-Only feature, displayed when a website is opened via HTTP, lacked an anti-clickjacking delay, potentially allowing an attacker to trick a user into granting an exception and loading a webpage over HTTP. This vulnerability was fixed in Firefox 140 and Thunderbird 140.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00283 20th percentileScored 2026-11-07
Fix Fixed Firefox (Mozilla): 140Thunderbird (Mozilla): 140

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
MozillaFirefox—140Patch availableCNA
MozillaThunderbird—140Patch availableCNA
  • Firefox VendorMozilla Affected — Fixed in 140 Patch available CNA
  • Thunderbird VendorMozilla Affected — Fixed in 140 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*before 140.0VulnerableMozilla
  • cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:* Versions before 140.0 Vulnerable ·Mozilla

Remediation

  • Fix · CNA Firefox (Mozilla) Fixed in 140
  • Fix · CNA Thunderbird (Mozilla) Fixed in 140

Vendor assessments

Red Hat

Red Hat rating: Low. Red Hat's page for this CVE →

Not affected: 5 products
  • Red Hat Enterprise Linux 10
  • Red Hat Enterprise Linux 6
  • Red Hat Enterprise Linux 7
  • Red Hat Enterprise Linux 8
  • Red Hat Enterprise Linux 9

Timeline

  1. 2026-10-02 Threatist record created from CVE-2025-6434
  2. 2026-10-03 Alias added: GHSA-87mm-rg9r-h8wm

References

Advisory 1

Other 2

  • TI-2024-08981 Use after free in Mozilla Firefox KEVCVSS 3.1CRITICAL 9.8
  • TI-2022-09832 Use after free in Mozilla Firefox KEVCVSS 3.1CRITICAL 9.6
  • TI-2019-08769 Improper input validation in Mozilla Firefox ESR KEVCVSS 3.1CRITICAL 10.0
  • TI-2010-03577 Mozilla Firefox 3.5.x through 3.5.14 and 3.6.x through 3.6.11, Thunderbird 3.1.6 before… KEVCVSS 3.1CRITICAL 9.8
  • TI-2023-04799 Out-of-bounds write in Google Chrome KEVCVSS 3.1HIGH 8.8
  • TI-2023-04477 Out-of-bounds write in Google Chrome KEVCVSS 3.1HIGH 8.8
See all 3444 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences