How severe is CVE-2026-64637?

CVE-2026-64637 has a CVSS 3.x base score of 9.9, rated critical severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-64637 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (18th percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-64637?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2026-64637 published?

CVE-2026-64637 was published on 2026-08-07.

CVE-2026-64637

CVE-2026-64637 is a critical-severity vulnerability with a CVSS 3.x base score of 9.9. 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-269.

Key facts

Severity: Critical (CVSS 3.x base score 9.9)
EPSS exploit prediction: 0% (18th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-269
Published: 2026-08-07
Last modified: 2026-08-07

Description

Improper privilege management in the XML-RPC API of Plesk before 18.0.80, allows an authenticated reseller to obtain an administrative session for the root user account.

Frequently asked questions

What is CVE-2026-64637?: Improper privilege management in the XML-RPC API of Plesk before 18.0.80, allows an authenticated reseller to obtain an administrative session for the root user account.
How severe is CVE-2026-64637?: CVE-2026-64637 has a CVSS 3.x base score of 9.9, rated critical severity. It is exploitable over network with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-64637 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (18th percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-64637?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2026-64637 published?: CVE-2026-64637 was published on 2026-08-07.

References

https://support.plesk.com/hc/en-us/articles/42432168683799

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