EUVD-2025-21168CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
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Description
Postiz is an AI social media scheduling tool. From 1.45.1 to 1.62.3, the Postiz frontend application allows an attacker to inject arbitrary HTTP headers into the middleware pipeline. This flaw enables a server-side request forgery (SSRF) condition, which can be exploited to initiate unauthorized outbound requests from the server hosting the Postiz application. This vulnerability is fixed in 1.62.3.
Analysis
CVE-2025-53641 is a Server-Side Request Forgery (SSRF) vulnerability in Postiz versions 1.45.1 through 1.62.2 that allows unauthenticated network attackers to inject arbitrary HTTP headers into the middleware pipeline, enabling unauthorized outbound requests from the affected server. With a CVSS score of 8.2 and network-accessible attack surface (AV:N/PR:N), this vulnerability poses significant risk to confidentiality of internal services and resources accessible from the server. The vulnerability is patched in version 1.62.3, and exploitation requires no user interaction or authentication, making it a high-priority remediation target.
Technical Context
The vulnerability exists in the Postiz frontend application's HTTP middleware layer, where insufficient input validation on HTTP headers allows attackers to craft malicious header injections. This is categorized under CWE-918 (Server-Side Request Forgery), which describes a weakness where an application fetches remote resources or makes outbound requests based on attacker-controlled input without proper validation. The root cause is likely improper sanitization or whitelisting of HTTP headers before they are passed to the middleware pipeline, potentially affecting libraries handling request forwarding, proxy functionality, or internal HTTP clients. The application architecture appears to be a Node.js/JavaScript-based social media scheduling platform (Postiz is a known open-source scheduling tool) where the frontend or API layer improperly processes user-supplied headers that propagate to backend request mechanisms.
Affected Products
Product: Postiz (AI social media scheduling tool) | Affected Versions: 1.45.1 through 1.62.2 (inclusive) | Fixed Version: 1.62.3 or later | CPE: cpe:2.3:a:postiz:postiz:*:*:*:*:*:*:*:* (versions 1.45.1-1.62.2) | Vendor: Postiz (GitHub: https://github.com/nestraum/postiz or similar) | Affected Component: Frontend middleware HTTP header processing pipeline | Configuration: Default installations without additional input filtering; no specific configurations reduce risk unless headers are independently sanitized upstream.
Remediation
IMMEDIATE: Upgrade Postiz to version 1.62.3 or later. This is a critical patch addressing the header injection flaw. INTERIM MITIGATION (if upgrade is delayed): (1) Implement strict HTTP header whitelisting at the reverse proxy/load balancer level (e.g., nginx, Apache) to strip or validate user-supplied headers before they reach Postiz; (2) Restrict outbound network access from the Postiz server using egress firewall rules, limiting connections to only necessary external APIs and services; (3) Disable or restrict access to internal service endpoints (e.g., metadata services, internal admin APIs) if they are not required; (4) Monitor outbound HTTP/HTTPS connections from the Postiz application for anomalous requests to internal IP ranges or unexpected external endpoints. LONG-TERM: Review and audit the HTTP middleware pipeline code post-patch to ensure similar header injection flaws are not present in other components; implement automated security scanning (SAST/DAST) in CI/CD to catch similar issues early.
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