How severe is CVE-2025-5020?

CVE-2025-5020 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity low, and availability none.

Is CVE-2025-5020 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (10th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-5020?

CVE-2025-5020 affects Mozilla Firefox. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2025-5020?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2025-5020 have an EU (EUVD) identifier?

Yes. CVE-2025-5020 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-16036.

When was CVE-2025-5020 published?

CVE-2025-5020 was published on 2025-05-21 and last updated on 2026-06-17.

CVE-2025-5020

CVE-2025-5020 is a medium-severity vulnerability in Mozilla Firefox with a CVSS 3.x base score of 4.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-939.

Key facts

Severity: Medium (CVSS 3.x base score 4.3)
EPSS exploit prediction: 0% (10th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-16036
Weakness: CWE-939
Affected product: Mozilla Firefox
Published: 2025-05-21
Last modified: 2026-06-17

Description

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 139.

Frequently asked questions

What is CVE-2025-5020?: 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 139.
How severe is CVE-2025-5020?: CVE-2025-5020 has a CVSS 3.x base score of 4.3, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity low, and availability none.
Is CVE-2025-5020 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (10th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-5020?: CVE-2025-5020 affects Mozilla Firefox. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2025-5020?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2025-5020 have an EU (EUVD) identifier?: Yes. CVE-2025-5020 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-16036.
When was CVE-2025-5020 published?: CVE-2025-5020 was published on 2025-05-21 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:mozilla:firefox:*:*:*:*:*:iphone_os:*:*

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