// For flags

CVE-2025-6434

HTTPS-Only exception screen lacked anti-clickjacking delay

Severity Score

4.3
*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

Track
*SSVC
Descriptions

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 affects Firefox < 140.

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 affects Firefox < 140 and Thunderbird < 140.

These are all security issues fixed in the MozillaThunderbird-140.1.0-1.1 package on the GA media of openSUSE Tumbleweed.

*Credits: hafiizh & kang ali
CVSS Scores
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None
Attack Vector
Network
Attack Complexity
Low
Authentication
None
Confidentiality
None
Integrity
Partial
Availability
None
* Common Vulnerability Scoring System
SSVC
  • Decision:Track
Exploitation
None
Automatable
No
Tech. Impact
Partial
* Organization's Worst-case Scenario
Timeline
  • 2025-06-20 CVE Reserved
  • 2025-06-24 CVE Published
  • 2025-10-30 CVE Updated
  • 2025-12-02 EPSS Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
  • CWE-1021: Improper Restriction of Rendered UI Layers or Frames
CAPEC
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
Mozilla
Search vendor "Mozilla"
 Firefox
Search vendor "Mozilla" for product "Firefox"
*-
Affected
Mozilla
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 Thunderbird
Search vendor "Mozilla" for product "Thunderbird"
*-
Affected
Fedoraproject
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 Fedora
Search vendor "Fedoraproject" for product "Fedora"
*-
Affected
Freebsd
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 Freebsd
Search vendor "Freebsd" for product "Freebsd"
*-
Affected
Slackware
Search vendor "Slackware"
 Slackware Linux
Search vendor "Slackware" for product "Slackware Linux"
*-
Affected