How severe is CVE-2025-3839?

CVE-2025-3839 has a CVSS 3.x base score of 8.0, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability none.

Is CVE-2025-3839 being actively exploited?

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

How do I fix CVE-2025-3839?

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-2025-3839 have an EU (EUVD) identifier?

Yes. CVE-2025-3839 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-4436.

When was CVE-2025-3839 published?

CVE-2025-3839 was published on 2026-01-23 and last updated on 2026-06-17.

CVE-2025-3839

CVE-2025-3839 is a high-severity vulnerability with a CVSS 3.x base score of 8.0. 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-356.

Key facts

Severity: High (CVSS 3.x base score 8.0)
EPSS exploit prediction: 0% (30th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-4436
Weakness: CWE-356
Published: 2026-01-23
Last modified: 2026-06-17

Description

A flaw was found in Epiphany, a tool that allows websites to open external URL handler applications with minimal user interaction. This design can be misused to exploit vulnerabilities within those handlers, making them appear remotely exploitable. The browser fails to properly warn or gate this action, resulting in potential code execution on the client device via trusted UI behavior.

Frequently asked questions

What is CVE-2025-3839?: A flaw was found in Epiphany, a tool that allows websites to open external URL handler applications with minimal user interaction. This design can be misused to exploit vulnerabilities within those handlers, making them appear remotely exploitable. The browser fails to properly warn or gate this action, resulting in potential code execution on the client device via trusted UI behavior.
How severe is CVE-2025-3839?: CVE-2025-3839 has a CVSS 3.x base score of 8.0, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2025-3839 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (30th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2025-3839?: 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-2025-3839 have an EU (EUVD) identifier?: Yes. CVE-2025-3839 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-4436.
When was CVE-2025-3839 published?: CVE-2025-3839 was published on 2026-01-23 and last updated on 2026-06-17.

References

Other CWE-356 vulnerabilities

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