Cyber Resilience

CVE-2025-27426

Open Redirect in Mozilla Firefox ≤ 136.0

Open Redirect
Published
04 March 2025
Modified
13 April 2026
Patch / advisory
View advisory
CVSS Score v3.1 5.4
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
EPSS Score 0.0023 14th percentile
Risk Priority 43 floored blend · peak EPSS

Summary

CVE-2025-27426 is a medium-severity Open Redirect (CWE-601) vulnerability in Mozilla Firefox. Its CVSS base score is 5.4 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Phishing (T1566); ranked at the 14th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SI-10 (Information Input Validation) and AC-4 (Information Flow Enforcement) — see the control section below for these in your framework.

OWASP Top 10 for Web (2025)

A01:2025 Broken Access Control

EU & UK References

Vulnerability Data

Malicious websites utilizing a server-side redirect to an internal error page could result in a spoofed website URL. This vulnerability was fixed in Firefox for iOS 136.

CWE(s)
CWE-601

Related Threats

MITRE ATT&CK Enterprise Techniques

T1566 Phishing Initial Access
Adversaries may send phishing messages to gain access to victim systems.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2025-27424Same product: Apple Iphone Os
CVE-2023-49061Same product: Mozilla Firefox
CVE-2025-54145Same product: Mozilla Firefox
CVE-2025-0244Same product: Mozilla Firefox
CVE-2024-0953Same product: Mozilla Firefox
CVE-2025-54144Same product: Mozilla Firefox
CVE-2024-4773Same product: Mozilla Firefox
CVE-2023-34415Same product: Mozilla Firefox
CVE-2025-27425Same product: Apple Iphone Os
CVE-2024-31392Same product: Apple Iphone Os

Affected Assets

mozilla
firefox
≤ 136.0

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V3.7.2

Mitigating Controls (NIST 800-53 r5) AI

SI-10 Information Input Validation good match

Input validation directly checks and rejects untrusted redirect targets before they are used in a response.

AC-4 Information Flow Enforcement partial match

Information flow enforcement can restrict redirects to only approved/trusted destinations, stopping untrusted user-supplied URLs from being followed.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly require input validation and untrusted-redirect controls that prevent CWE-601.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.23 Web filtering partial match
mitigates

Preventing access to attacker-controlled or malicious sites stops users from being redirected to untrusted locations via open-redirect or phishing links.

References