CVE-2026-43633 HestiaCP 1.9.0-1.9.4 Deserialization RCE via Web Terminal
Unauthenticated attackers can achieve root-level code execution via deserialization in the web terminal component when enabled.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-43633?
CVE-2026-43633 is a critical unsafe deserialization vulnerability in hestiacp, published on 19 May 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official 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.
Weakness: CWE-502
Which versions are affected by CVE-2026-43633?
How do I fix CVE-2026-43633?
No fix has been published for CVE-2026-43633 yet. Limit exposure of the affected software until one is available.
Upgrade, and only deserialise data from trusted sources or with an allow-list of types. More about Unsafe deserialization.
Is CVE-2026-43633 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-43633 exists.
Sources
Also known as GHSA-p57r-8pg4-2892.