How severe is CVE-2025-55300?

CVE-2025-55300 has a CVSS 4.0 base score of 8.6, rated high severity.

Is CVE-2025-55300 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (40th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2025-55300?

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-2025-55300 have an EU (EUVD) identifier?

Yes. CVE-2025-55300 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-25135.

When was CVE-2025-55300 published?

CVE-2025-55300 was published on 2025-08-18 and last updated on 2026-06-17.

CVE-2025-55300

CVE-2025-55300 is a high-severity vulnerability with a CVSS 4.0 base score of 8.6. 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 4.0 base score 8.6)
EPSS exploit prediction: 1% (40th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2025-25135
Weakness: CWE-79
Published: 2025-08-18
Last modified: 2026-06-17

Description

Komari is a lightweight, self-hosted server monitoring tool designed to provide a simple and efficient solution for monitoring server performance. Prior to 1.0.4-fix1, WebSocket upgrader has disabled origin checking, enabling Cross-Site WebSocket Hijacking (CSWSH) attacks against authenticated users. Any third party website can send requests to the terminal websocket endpoint with browser's cookies, resulting in remote code execution. This vulnerability is fixed in 1.0.4-fix1.

Frequently asked questions

What is CVE-2025-55300?: Komari is a lightweight, self-hosted server monitoring tool designed to provide a simple and efficient solution for monitoring server performance. Prior to 1.0.4-fix1, WebSocket upgrader has disabled origin checking, enabling Cross-Site WebSocket Hijacking (CSWSH) attacks against authenticated users. Any third party website can send requests to the terminal websocket endpoint with browser's cookies, resulting in remote code execution. This vulnerability is fixed in 1.0.4-fix1.
How severe is CVE-2025-55300?: CVE-2025-55300 has a CVSS 4.0 base score of 8.6, rated high severity.
Is CVE-2025-55300 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (40th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2025-55300?: 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-2025-55300 have an EU (EUVD) identifier?: Yes. CVE-2025-55300 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-25135.
When was CVE-2025-55300 published?: CVE-2025-55300 was published on 2025-08-18 and last updated on 2026-06-17.

References

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