How severe is CVE-2025-6426?

CVE-2025-6426 has a CVSS 3.x base score of 8.8, 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 high.

Is CVE-2025-6426 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (7th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2025-6426?

CVE-2025-6426 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-2025-6426?

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-2025-6426 have an EU (EUVD) identifier?

Yes. CVE-2025-6426 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-19102.

When was CVE-2025-6426 published?

CVE-2025-6426 was published on 2025-06-24 and last updated on 2026-06-17.

CVE-2025-6426

CVE-2025-6426 is a high-severity vulnerability in Mozilla Firefox with a CVSS 3.x base score of 8.8. 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-345.

Key facts

Severity: High (CVSS 3.x base score 8.8)
EPSS exploit prediction: 0% (7th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-19102
Weakness: CWE-345
Affected product: Mozilla Firefox
Published: 2025-06-24
Last modified: 2026-06-17

Description

The executable file warning did not warn users before opening files with the `terminal` extension. *This bug only affects Firefox for macOS. Other versions of Firefox are unaffected.*. This vulnerability was fixed in Firefox 140, Firefox ESR 128.12, Thunderbird 140, and Thunderbird 128.12.

Frequently asked questions

What is CVE-2025-6426?: The executable file warning did not warn users before opening files with the `terminal` extension. *This bug only affects Firefox for macOS. Other versions of Firefox are unaffected.*. This vulnerability was fixed in Firefox 140, Firefox ESR 128.12, Thunderbird 140, and Thunderbird 128.12.
How severe is CVE-2025-6426?: CVE-2025-6426 has a CVSS 3.x base score of 8.8, 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 high.
Is CVE-2025-6426 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (7th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2025-6426?: CVE-2025-6426 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-2025-6426?: 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-2025-6426 have an EU (EUVD) identifier?: Yes. CVE-2025-6426 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-19102.
When was CVE-2025-6426 published?: CVE-2025-6426 was published on 2025-06-24 and last updated on 2026-06-17.

References

Affected products (2)

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

More vulnerabilities in Mozilla Firefox

CVE-2026-4725 — Critical (CVSS 10.0): Sandbox escape due to use-after-free in the Graphics: Canvas2D component. This vulnerability was fixed in Firefox 149…
CVE-2026-4692 — Critical (CVSS 10.0): Sandbox escape in the Responsive Design Mode component. This vulnerability was fixed in Firefox 149, Firefox ESR…
CVE-2026-4689 — Critical (CVSS 10.0): Sandbox escape due to incorrect boundary conditions, integer overflow in the XPCOM component. This vulnerability was…
CVE-2026-4688 — Critical (CVSS 10.0): Sandbox escape due to use-after-free in the Disability Access APIs component. This vulnerability was fixed in Firefox…
CVE-2026-2778 — Critical (CVSS 10.0): Sandbox escape due to incorrect boundary conditions in the DOM: Core & HTML component. This vulnerability was fixed in…
CVE-2026-2776 — Critical (CVSS 10.0): Sandbox escape due to incorrect boundary conditions in the Telemetry component in External Software. This vulnerability…

All CVEs affecting Mozilla Firefox →

Other CWE-345 (Insufficient Verification of Data Authenticity) vulnerabilities

CVE-2026-35051 — Critical (CVSS 10.0): Traefik is an HTTP reverse proxy and load balancer. Prior to versions 2.11.43, 3.6.14, and 3.7.0-rc.2, there is an…
CVE-2014-8165 — Critical (CVSS 10.0): scripts/amsvis/powerpcAMS/amsnet.py in powerpc-utils-python uses the pickle Python module unsafely, which allows remote…
CVE-2026-50195 — Critical (CVSS 9.9): containerd is an open-source container runtime. Versions prior to 2.3.2, 2.2.5 and 2.1.9 contain a vulnerability in the…
CVE-2022-36130 — Critical (CVSS 9.9): HashiCorp Boundary up to 0.10.1 did not properly perform data integrity checks to ensure the resources were associated…
CVE-2026-50214 — Critical (CVSS 9.8): The /v1/Plan service relies entirely on a shared global API token for full administrative management, allowing…
CVE-2025-15385 — Critical (CVSS 9.8): Insufficient Verification of Data Authenticity vulnerability in TECNO Mobile com.Afmobi.Boomplayer allows…

Browse all CWE-345 (Insufficient Verification of Data Authenticity) vulnerabilities →