How severe is CVE-2025-42959?

CVE-2025-42959 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2025-42959 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (39th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2025-42959?

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-2025-42959 have an EU (EUVD) identifier?

Yes. CVE-2025-42959 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-20350.

When was CVE-2025-42959 published?

CVE-2025-42959 was published on 2025-07-08 and last updated on 2026-06-17.

CVE-2025-42959

CVE-2025-42959 is a high-severity vulnerability 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-308.

Key facts

Severity: High (CVSS 3.x base score 8.1)
EPSS exploit prediction: 0% (39th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-20350
Weakness: CWE-308
Published: 2025-07-08
Last modified: 2026-06-17

Description

An unauthenticated attacker may exploit a scenario where a Hashed Message Authentication Code (HMAC) credential, extracted from a system missing specific security patches, is reused in a replay attack against a different system. Even if the target system is fully patched, successful exploitation could result in complete system compromise, affecting confidentiality, integrity, and availability.

Frequently asked questions

What is CVE-2025-42959?: An unauthenticated attacker may exploit a scenario where a Hashed Message Authentication Code (HMAC) credential, extracted from a system missing specific security patches, is reused in a replay attack against a different system. Even if the target system is fully patched, successful exploitation could result in complete system compromise, affecting confidentiality, integrity, and availability.
How severe is CVE-2025-42959?: CVE-2025-42959 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with high attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2025-42959 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (39th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2025-42959?: 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-2025-42959 have an EU (EUVD) identifier?: Yes. CVE-2025-42959 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-20350.
When was CVE-2025-42959 published?: CVE-2025-42959 was published on 2025-07-08 and last updated on 2026-06-17.

References

Other CWE-308 vulnerabilities

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CVE-2024-47652 — High (CVSS 8.1): This vulnerability exists in Shilpi Client Dashboard due to implementation of inadequate authentication mechanism in…
CVE-2024-27928 — Medium (CVSS 5.9): vantage6 is an open-source infrastructure for privacy preserving analysis. Prior to version 5.0.0, if an attacker hacks…
CVE-2026-56022 — Medium (CVSS 5.3): Webmin accepts basic authentication without session cookies when an attacker provides the 'User-Agent: webmin' header,…
CVE-2023-25681 — Medium (CVSS 5.3): LDAP users on IBM Spectrum Virtualize 8.5 which are configured to require multifactor authentication can still…

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