Vulnerability · Published Jan 23, 2026 · Assigned by zdi

CVE-2026-0773Upsonic Cloudpickle Deserialization of Untrusted Data Remote Code Execution Vulnerability

Critical 9.8

In plain English

A critical-severity unsafe deserialization in Upsonic from Upsonic. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 1.4% (higher than 73% of all known vulnerabilities).

Severity (CVSS 3.0)9.8Critical

Exploit odds (30 days)1.4%top 26.7% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

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.

Affected products (as reported)

Vendor	Product	Versions
Upsonic	Upsonic	0.52.1

Weakness: CWE-502 · Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

References

ZDI-26-042 x_research-advisory