CVE-2025-6279 is a deserialization vulnerability identified in the Upsonic software, specifically affecting versions up to 0.55.6. The vulnerability resides in the cloudpickle.loads function within the /tools/add_tool component, known as the Pickle Handler. Deserialization vulnerabilities occur when untrusted data is deserialized, allowing attackers to manipulate the input to execute arbitrary code or cause unexpected behavior. In this case, the vulnerability allows an attacker with low privileges (PR:L) and remote access (AV:A) to exploit the deserialization process without requiring user interaction (UI:N) or authentication tokens (AT:N). The vulnerability impacts confidentiality, integrity, and availability at a low level (VC:L, VI:L, VA:L), indicating potential but limited data exposure or system disruption. The CVSS 4.0 base score is 5.1, categorizing it as medium severity. The exploit has been publicly disclosed but there are no known exploits actively used in the wild at this time. The vulnerability’s attack vector is adjacent network, meaning the attacker must have some network access to the vulnerable system, but not necessarily full network access. The low attack complexity (AC:L) suggests that exploitation does not require sophisticated conditions. The vulnerability does not affect system scope or security attributes (SC:N, SI:N, SA:N), indicating the impact is confined to the vulnerable component without privilege escalation or system-wide compromise. Overall, the vulnerability allows an attacker with limited privileges and network access to potentially execute malicious code or manipulate the system through crafted serialized data, posing a moderate risk to affected installations of Upsonic prior to version 0.55.7.

For European organizations using Upsonic versions up to 0.55.6, this vulnerability presents a moderate risk. Upsonic is typically used in environments requiring data serialization and deserialization, possibly in data processing or automation workflows. Exploitation could lead to unauthorized code execution, data manipulation, or service disruption, impacting confidentiality, integrity, and availability of critical systems. While the attack vector requires adjacent network access and low privileges, the lack of required user interaction lowers the barrier for exploitation in internal or segmented network environments. European organizations with sensitive data or critical infrastructure relying on Upsonic could face operational disruptions or data breaches if this vulnerability is exploited. The absence of known active exploits reduces immediate risk, but public disclosure increases the likelihood of future exploitation attempts. Given the medium severity and potential for lateral movement within networks, organizations should prioritize remediation to prevent escalation and protect sensitive assets.

1. Upgrade Upsonic to version 0.55.7 or later where this vulnerability is patched. If an upgrade is not immediately possible, implement strict network segmentation to limit adjacent network access to systems running vulnerable Upsonic versions. 2. Employ application-layer filtering or input validation to detect and block malicious serialized data inputs targeting the cloudpickle.loads function. 3. Monitor network traffic and application logs for unusual deserialization activity or anomalies related to the /tools/add_tool endpoint. 4. Restrict privileges of users and services interacting with Upsonic to the minimum necessary to reduce the impact of potential exploitation. 5. Consider deploying runtime application self-protection (RASP) or endpoint detection and response (EDR) solutions capable of detecting deserialization attacks. 6. Conduct regular security assessments and penetration testing focusing on deserialization vulnerabilities in internal applications. 7. Educate development and operations teams about secure deserialization practices and the risks of using unsafe deserialization functions like cloudpickle.loads with untrusted input.