Cyber Resilience

CVE-2025-5020

Medium

Published: 21 May 2025

Published
21 May 2025
Modified
13 April 2026
KEV Added
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Patch
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CVSS Score v3.1 4.3 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:L/A:N
EPSS Score 0.0018 39.6th percentile
Risk Priority 9 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2025-5020 is a medium-severity Improper Authorization in Handler for Custom URL Scheme (CWE-939) vulnerability in Mozilla Firefox. Its CVSS base score is 4.3 (Medium).

Operationally, ranked at the 39.6th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability details

Opening maliciously-crafted URLs in Firefox from other apps such as Safari could have allowed attackers to spoof website addresses if the URLs utilized non-HTTP schemes used internally by the Firefox iOS client. This vulnerability was fixed in Firefox for iOS…

more

139.

CWE(s)
CWE-939

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

mozilla
firefox
≤ 139.0

Mitigating Controls

No mitigating controls mapped yet. The per-CVE control annotator has not reached this CVE.

References