Music Player Daemon CVE-2026-49129

Two hard technical prerequisites must both be met: (1) the target system must be running libcurl < 7.85.0 - systems with libcurl >= 7.85.0 restrict redirect protocols by default and are not exploitable even on unpatched MPD versions; (2) the attacker must have access to MPD's command interface (TCP 6600 or configured Unix socket) to issue URL-accepting commands (add, readcomments, albumart, readpicture, or load). CVSS PR:N confirms no MPD-level authentication is required once the command port is reachable. The attacker must also control or compromise an intermediate HTTP server capable of serving protocol-switching redirects. Exploitation is limited by MPD's typical deployment as a local media daemon bound to localhost, which requires the attacker to already have local network access or a means to reach the command port. Non-default external binding of the command socket significantly elevates real-world risk.

The CVSS 4.0 vector AV:N/AC:L/AT:N/PR:N/UI:N places this in the unauthenticated, low-complexity, no-prerequisites category - the highest possible exploitability rating. However, the impact metrics temper this: VC:N/VI:N/VA:N (no direct impact on the vulnerable component itself) and SC:L/SI:N/SA:N (only low subsequent-system confidentiality impact) cap the overall score at 6.9. This scoring profile is consistent with a classic blind SSRF: the attacker cannot directly read MPD's memory or crash it, but can weaponize it as a pivot to probe internal services. EPSS data was not provided in the input and cannot be stated. The vulnerability is not listed in CISA KEV, and no POC code was referenced in the provided intelligence. Real-world risk is strongly tied to deployment context: MPD is typically a local media daemon (TCP 6600 bound to localhost), which significantly narrows the attack surface compared to a public-facing web service. Organizations exposing MPD to untrusted networks face materially higher risk. The dependency on libcurl < 7.85.0 also acts as a natural limiting factor, as modern Linux distributions shipping libcurl >= 7.85.0 are not exploitable regardless of MPD version.

An attacker with network access to MPD's command port (TCP 6600) issues a command such as add http://attacker-controlled.example.com/redirect.m3u where the attacker's HTTP server responds with a 301 redirect to gopher://internal-db-server:6379/_PING (or an LDAP, FTP, or SMTP endpoint). MPD's libcurl follows the redirect without protocol restriction, causing MPD to transmit a crafted payload to the internal service on behalf of the attacker. This enables blind SSRF-based reconnaissance or interaction with internal services that are unreachable directly from the attacker's network.