CVE intelligence and bounded remediation
CVE-2026-43633 — HestiaCP security vulnerability
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.
- Severity
- Critical
- CVSS
- 10 (3.1)
- Published
- 2026-05-19
- CISA KEV
- Not currently listed
- Ecosystem
- javascript/npm
- Weaknesses
- CWE-502
Affected products
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Matched remediation archetype
Unsafe deserialization and object reconstruction
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Check exposure
- Inventory serialization formats accepted from requests, queues, caches, files, cookies, and cross-service messages.
- Trace whether untrusted input can select classes, types, callbacks, constructors, or object hooks during decoding.
- Identify signing, schema validation, trust-boundary, and compatibility settings for each decoder.
Remediate safely
- Replace native object deserialization with a data-only format and explicit schema validation.
- If replacement is not immediate, use a safe decoder with a minimal type allowlist and disable polymorphic or executable hooks.
- Update the affected library and add inert tests for unknown types, extra fields, malformed nesting, and unsigned data.
Authoritative sources
Complete CVE record and remediation plan
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