How severe is CVE-2025-8039?

CVE-2025-8039 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability none.

Is CVE-2025-8039 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (20th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-8039?

CVE-2025-8039 primarily affects Mozilla Firefox. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2025-8039?

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-2025-8039 have an EU (EUVD) identifier?

Yes. CVE-2025-8039 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-22363.

When was CVE-2025-8039 published?

CVE-2025-8039 was published on 2025-07-22 and last updated on 2026-06-17.

CVE-2025-8039

CVE-2025-8039 is a high-severity vulnerability in Mozilla Firefox with a CVSS 3.x base score of 8.1. 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-200.

Key facts

Severity: High (CVSS 3.x base score 8.1)
EPSS exploit prediction: 0% (20th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-22363
Weakness: CWE-200
Affected product: Mozilla Firefox
Published: 2025-07-22
Last modified: 2026-06-17

Description

In some cases search terms persisted in the URL bar even after navigating away from the search page. This vulnerability was fixed in Firefox 141, Firefox ESR 140.1, Thunderbird 141, and Thunderbird 140.1.

Frequently asked questions

What is CVE-2025-8039?: In some cases search terms persisted in the URL bar even after navigating away from the search page. This vulnerability was fixed in Firefox 141, Firefox ESR 140.1, Thunderbird 141, and Thunderbird 140.1.
How severe is CVE-2025-8039?: CVE-2025-8039 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability none.
Is CVE-2025-8039 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (20th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-8039?: CVE-2025-8039 primarily affects Mozilla Firefox. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2025-8039?: 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-2025-8039 have an EU (EUVD) identifier?: Yes. CVE-2025-8039 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-22363.
When was CVE-2025-8039 published?: CVE-2025-8039 was published on 2025-07-22 and last updated on 2026-06-17.

References

Affected products (4)

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

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