Is CVE-2025-4093 in the CISA KEV catalog?

No. CVE-2025-4093 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2025-4093?

CVE-2025-4093 has a CVSS v3 base score of 8.1 (HIGH).

What is the EPSS score for CVE-2025-4093?

CVE-2025-4093 has an EPSS score of 0.39% (30th percentile), estimating the probability of exploitation in the next 30 days.

CVE & CISA-KEV Catalog

CVE-2025-4093

HIGH

8.1

CVSS v3

NVD

Description

Memory safety bug present in Firefox ESR 128.9, and Thunderbird 128.9. This bug showed evidence of memory corruption and we presume that with enough effort this could have been exploited to run arbitrary code. This vulnerability was fixed in Firefox ESR 128.10 and Thunderbird 128.10.

CWE-119Buffer Overflow

CVSS v3 Vector

Exploitability

Attack VectorNetwork

Attack ComplexityHigh

Privileges RequiredNone

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploit Intelligence

0.39%probability of exploitation in 30 days

30thpercentile

Low risk: more likely to be exploited than 30% of all known CVEs.

References

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-04-13.