CVE-2026-0773 Upsonic Cloudpickle Deserialization of Untrusted Data Remote Code Execution Vulnerability
Remote attackers can execute arbitrary code via untrusted data deserialization in the add_tool endpoint without authentication.
- 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-2026-0773?
CVE-2026-0773 is a critical unsafe deserialization vulnerability in Upsonic, published on 23 Jan 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Upsonic Cloudpickle Deserialization of Untrusted Data Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of Upsonic. Authentication is not required to exploit this vulnerability.
The specific flaw exists within the add_tool endpoint, which listens on TCP port 7541 by default. The issue results from the lack of proper validation of user-supplied data, which can result in deserialization of untrusted data. An attacker can leverage this vulnerability to execute code in the context of the service account. Was ZDI-CAN-26845.
Weakness: CWE-502
Which versions are affected by CVE-2026-0773?
How do I fix CVE-2026-0773?
No fix has been published for CVE-2026-0773 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-2026-0773 being exploited?
There is no known exploitation of CVE-2026-0773 in the wild and no public exploit code.
Sources
Also known as GHSA-8rrj-mw9c-258v.