CVE-2025-44594 identifies a server-side request forgery (SSRF) vulnerability in the Halo software version 2.20.17 and earlier. The vulnerability exists in the API endpoint /apis/uc.api.storage.halo.run/v1alpha1/attachments/-/upload-from-url, which allows users to upload attachments by specifying a URL. SSRF vulnerabilities occur when an attacker can manipulate a server to make HTTP requests to arbitrary domains or internal network resources, potentially bypassing firewall restrictions and accessing sensitive internal services. In this case, the vulnerable endpoint does not properly validate or restrict the URLs provided for uploading attachments, enabling an attacker to coerce the server into fetching resources from unintended locations. This can lead to unauthorized internal network scanning, access to internal-only services, or exploitation of other vulnerabilities within the internal network. Although no known exploits are currently reported in the wild, the presence of this SSRF in a publicly exposed API endpoint presents a significant risk. The lack of a CVSS score indicates that the vulnerability has not yet been fully assessed for impact severity, but the nature of SSRF vulnerabilities typically allows attackers to pivot within the network or exfiltrate sensitive data. The affected versions are all versions up to 2.20.17, but no specific patch or mitigation link is provided, suggesting that users should urgently seek updates or vendor guidance. The vulnerability was reserved in April 2025 and published in September 2025, indicating recent discovery and disclosure.

For European organizations using Halo software, this SSRF vulnerability could have serious consequences. If the vulnerable API endpoint is exposed to the internet or accessible within corporate networks, attackers could exploit it to access internal services that are otherwise protected by network segmentation or firewalls. This could lead to unauthorized data access, internal reconnaissance, or lateral movement within the network. Confidentiality could be compromised if sensitive internal resources are accessed or data exfiltrated. Integrity and availability impacts are also possible if attackers leverage SSRF to trigger further exploits or denial-of-service conditions on internal systems. Given the increasing adoption of cloud and hybrid environments in Europe, where internal services are often protected behind firewalls, SSRF vulnerabilities are particularly dangerous as they bypass perimeter defenses. The absence of known exploits suggests that exploitation is not widespread yet, but the vulnerability should be treated proactively to prevent future attacks. Organizations in sectors with high-value internal services, such as finance, healthcare, and critical infrastructure, are at elevated risk due to the potential for sensitive data exposure or disruption.

European organizations should immediately assess their use of Halo software and determine if they are running version 2.20.17 or earlier. In the absence of an official patch, organizations should consider the following specific mitigations: 1) Restrict access to the vulnerable API endpoint by implementing network-level controls such as IP whitelisting, VPN-only access, or web application firewalls (WAF) with rules to detect and block SSRF patterns. 2) Implement strict input validation and URL allowlisting on the upload-from-url parameter to ensure only trusted domains or internal URLs are accepted. 3) Monitor logs for unusual outbound requests initiated by the server, especially to internal IP ranges or unexpected external domains. 4) Employ network segmentation to limit the server's ability to reach sensitive internal resources. 5) Engage with the software vendor to obtain patches or updates addressing this vulnerability as soon as they become available. 6) Conduct penetration testing focused on SSRF to identify any other vulnerable endpoints. These targeted actions go beyond generic advice by focusing on controlling the vulnerable API's exposure and monitoring for exploitation attempts.