CVE-2025-6434
published 2025-06-24CVE-2025-6434: 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…
PriorityP419medium4.3CVSS 3.1
AVNACLPRNUIRSUCNILAN
EPSS
0.23%
13.4th percentile
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.
Affected
4 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | firefox | < firefox 140.0-1 (sid) | firefox 140.0-1 (sid) |
| mozilla | firefox | < 140.0 | 140.0 |
| mozilla | firefox | — | — |
| mozilla | thunderbird | >= 0 < 1:140.7.1+build1-0ubuntu0.22.04.1 | 1:140.7.1+build1-0ubuntu0.22.04.1 |
CVSS provenance
nvdv3.14.3MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
osv4.3MEDIUM
vendor_debian4.3MEDIUM
vendor_redhat4.3MEDIUM
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GHSA
GHSA-87mm-rg9r-h8wm: The exception page for the HTTPS-Only feature, displayed when a website is opened via HTTP, lacked an anti-clickjacking delay, potentially allowing an
ghsa_unreviewed·2025-06-26
CVE-2025-6434 [MEDIUM] CWE-1021 GHSA-87mm-rg9r-h8wm: The exception page for the HTTPS-Only feature, displayed when a website is opened via HTTP, lacked an anti-clickjacking delay, potentially allowing an
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.
OSV
CVE-2025-6434: The exception page for the HTTPS-Only feature, displayed when a website is opened via HTTP, lacked an anti-clickjacking delay, potentially allowing an
osv·2025-06-24·CVSS 4.3
CVE-2025-6434 [MEDIUM] CVE-2025-6434: The exception page for the HTTPS-Only feature, displayed when a website is opened via HTTP, lacked an anti-clickjacking delay, potentially allowing an
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.
Ubuntu
Thunderbird vulnerabilities
vendor_ubuntu·2026-02-02
CVE-2025-8031 Thunderbird vulnerabilities
Title: Thunderbird vulnerabilities
Summary: Several security issues were fixed in Thunderbird.
Multiple security issues were discovered in Thunderbird. If a user were
tricked into opening a specially crafted website in a browsing context,
an attacker could potentially exploit these to cause a denial of service,
obtain sensitive information, bypass security restrictions, cross-site
tracing, or execute arbitrary code.
Instructions: In general, a standard system update will make all the necessary changes.
Red Hat
firefox: HTTPS-Only exception screen lacked anti-clickjacking delay
vendor_redhat·2025-06-24·CVSS 4.3
CVE-2025-6434 [MEDIUM] firefox: HTTPS-Only exception screen lacked anti-clickjacking delay
firefox: HTTPS-Only exception screen lacked anti-clickjacking delay
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.
A flaw was found in Firefox. The Mozilla Foundation's Security Advisory describes the following issue:
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.
Statement: Red Hat Product Security rates the severity of this flaw as determined by the M
Debian
CVE-2025-6434: firefox - The exception page for the HTTPS-Only feature, displayed when a website is opene...
vendor_debian·2025·CVSS 4.3
CVE-2025-6434 [MEDIUM] CVE-2025-6434: firefox - The exception page for the HTTPS-Only feature, displayed when a website is opene...
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.
Scope: local
sid: resolved (fixed in 140.0-1)
Mozilla
Mozilla Foundation Security Advisory 2025-54: CVE-2025-6434
vendor_mozilla·CVSS 4.3
CVE-2025-6434 [MEDIUM] Mozilla Foundation Security Advisory 2025-54: CVE-2025-6434
Mozilla Foundation Security Advisory 2025-54
CVE: CVE-2025-6434
Product: Thunderbird
Impact: high
Fixed in: Thunderbird 140
Mozilla
Mozilla Foundation Security Advisory 2025-51: CVE-2025-6434
vendor_mozilla·CVSS 4.3
CVE-2025-6434 [MEDIUM] Mozilla Foundation Security Advisory 2025-51: CVE-2025-6434
Mozilla Foundation Security Advisory 2025-51
CVE: CVE-2025-6434
Product: Firefox
Impact: high
Fixed in: Firefox 140
No detection rules found.
No public exploits indexed.
2025-06-24
Published