What is CVE-2026-43633?

CVE-2026-43633 is a critical-severity vulnerability in Hestiacp, classified under Deserialization of Untrusted Data. CVSS score: 10.0/10. Published 2026-05-19.

How severe is CVE-2026-43633?

Critical severity. CVSS v3 base score is 10.0 out of 10.

Deserialization in Hestiacp

CVE-2026-43633

HestiaCP versions 1.9.0 through 1.9.4 contain a deserialization vulnerability in the web terminal component caused by a session format mismatch between PHP and Node.js that allows unauthenticated remote attackers to achieve root-level code…

Vulnerability class: Insecure Deserialization

EPSS: 0.002 (42.2th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 10.0 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H.

Affected products

Hestiacp — versions 1.9.0, 854d71b3c1737b0a0d0cc55c926008ffe1f6719b

Weakness classification (CWE)

CWE-502 — Deserialization of Untrusted Data

References

disclosure@vulncheck.com (issue-tracking, technical-description, exploit)
disclosure@vulncheck.com (issue-tracking)
disclosure@vulncheck.com (issue-tracking, patch)
disclosure@vulncheck.com (patch)
disclosure@vulncheck.com (third-party-advisory)

Frequently asked questions

What is CVE-2026-43633?: CVE-2026-43633 is a critical-severity vulnerability in Hestiacp, classified under Deserialization of Untrusted Data. CVSS score: 10.0/10. Published 2026-05-19.
How severe is CVE-2026-43633?: Critical severity. CVSS v3 base score is 10.0 out of 10.