CVE & CISA-KEV Catalog

CVE-2026-2634

CRITICAL
9.8
CVSS v3
NVD

Description

Malicious scripts could cause desynchronization between the address bar and web content before a response is received in Firefox iOS, allowing attacker-controlled pages to be presented under spoofed domains. This vulnerability was fixed in Firefox for iOS 147.4.

How to fix

Remediation Available
DeveloperEditionWindows application
Affected:147.4Fixed in:147.4Mozilla
Mozilla Firefox (en-US)Windows application
Affected:147.4Fixed in:147.4Mozilla

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone
ScopeUnchanged

Impact

ConfidentialityHigh
IntegrityHigh
AvailabilityHigh

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploit Intelligence

0.31%probability of exploitation in 30 days
23rdpercentile

Low risk: more likely to be exploited than 23% of all known CVEs.

References

Vendor Advisory1
Issue Tracking1

Related Vulnerabilities

Other CWE-451 vulnerabilities, ordered by exploit likelihood. View all

CVESeverityCVSSEPSSExploitedFix
CVE-2024-38112High7.584%KEVFix
CVE-2025-9491High7.869%--
CVE-2024-43461High8.852%KEVFix
CVE-2024-38197Medium6.516%--
CVE-2024-49040High7.57.7%-Fix
CVE-2026-0907Critical9.87.7%-Fix

Common questions

How do I fix CVE-2026-2634?

Published advisories record a fix for 2 affected products. The "How to fix" section on this page lists the fixed version and source advisory for each one, so apply the entry matching what you actually run.

Is CVE-2026-2634 being actively exploited?

Not that we know of. CVE-2026-2634 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.31% is the estimated probability that it will be exploited in the next 30 days. That is higher than 23% of all scored CVEs.

How severe is CVE-2026-2634?

CVE-2026-2634 has a CVSS v3 base score of 9.8, rated critical. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2026-2634 affect?

Published advisories record a fix for DeveloperEdition (Windows application), Mozilla Firefox (en-US) (Windows application). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-04-13.