What’s Vulnerable › Vulnerabilities

CVE-2026-43633: HestiaCP 1.9.0-1.9.4 Deserialization RCE via Web Terminal

• Severity: critical (CVSS 10.0 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-05-19 · updated 2026-07-14
• Weakness: CWE-502

Description

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 execution. Attackers can inject crafted data into HTTP headers that are processed by the PHP session handler but incorrectly deserialized by the Node.js web terminal component as trusted session values, resulting in arbitrary command execution on systems with the web terminal feature enabled.

Affected products

• hestiacp/hestiacp: from 1.9.0 through 1.9.4

References

• https://github.com/hestiacp/hestiacp/commit/854d71b3c1737b0a0d0cc55c926008ffe1f6719b
• https://github.com/hestiacp/hestiacp/issues/5229
• https://github.com/hestiacp/hestiacp/pull/5244
• https://mercuryiss.com.au/hestiacp-unauthenticated-rce-ip-spoofing-cve-2026-43633-cve-2026-43634
• https://www.vulncheck.com/advisories/hestiacp-deserialization-rce-via-web-terminal

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