How severe is CVE-2025-4085?

CVE-2025-4085 has a CVSS 3.x base score of 7.1, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity low, and availability none.

Is CVE-2025-4085 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (16th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-4085?

CVE-2025-4085 primarily affects Mozilla Firefox. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2025-4085?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

Does CVE-2025-4085 have an EU (EUVD) identifier?

Yes. CVE-2025-4085 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-12686.

When was CVE-2025-4085 published?

CVE-2025-4085 was published on 2025-04-29 and last updated on 2026-06-17.

CVE-2025-4085

CVE-2025-4085 is a high-severity vulnerability in Mozilla Firefox with a CVSS 3.x base score of 7.1. 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-269.

Key facts

Severity: High (CVSS 3.x base score 7.1)
EPSS exploit prediction: 0% (16th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-12686
Weakness: CWE-269
Affected product: Mozilla Firefox
Published: 2025-04-29
Last modified: 2026-06-17

Description

An attacker with control over a content process could potentially leverage the privileged UITour actor to leak sensitive information or escalate privileges. This vulnerability was fixed in Firefox 138 and Thunderbird 138.

Frequently asked questions

What is CVE-2025-4085?: An attacker with control over a content process could potentially leverage the privileged UITour actor to leak sensitive information or escalate privileges. This vulnerability was fixed in Firefox 138 and Thunderbird 138.
How severe is CVE-2025-4085?: CVE-2025-4085 has a CVSS 3.x base score of 7.1, rated high severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity low, and availability none.
Is CVE-2025-4085 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (16th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-4085?: CVE-2025-4085 primarily affects Mozilla Firefox. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2025-4085?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
Does CVE-2025-4085 have an EU (EUVD) identifier?: Yes. CVE-2025-4085 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-12686.
When was CVE-2025-4085 published?: CVE-2025-4085 was published on 2025-04-29 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:a:mozilla:firefox:*:*:*:*:-:*:*:*
cpe:2.3:a:mozilla:thunderbird:*:*:*:*:-:*:*:*

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