How severe is CVE-2025-10534?

CVE-2025-10534 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-2025-10534 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (25th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-10534?

CVE-2025-10534 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-2025-10534?

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-2025-10534 have an EU (EUVD) identifier?

Yes. CVE-2025-10534 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-29554.

When was CVE-2025-10534 published?

CVE-2025-10534 was published on 2025-09-16 and last updated on 2026-06-17.

CVE-2025-10534

CVE-2025-10534 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-79.

Key facts

Severity: High (CVSS 3.x base score 8.1)
EPSS exploit prediction: 0% (25th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-29554
Weakness: CWE-79
Affected product: Mozilla Firefox
Published: 2025-09-16
Last modified: 2026-06-17

Description

Spoofing issue in the Site Permissions component. This vulnerability was fixed in Firefox 143 and Thunderbird 143.

Frequently asked questions

What is CVE-2025-10534?: Spoofing issue in the Site Permissions component. This vulnerability was fixed in Firefox 143 and Thunderbird 143.
How severe is CVE-2025-10534?: CVE-2025-10534 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-2025-10534 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (25th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-10534?: CVE-2025-10534 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-2025-10534?: 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-2025-10534 have an EU (EUVD) identifier?: Yes. CVE-2025-10534 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-29554.
When was CVE-2025-10534 published?: CVE-2025-10534 was published on 2025-09-16 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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