Nixpkgs security tracker

Published

Permalink CVE-2026-77339

5.1 MEDIUM

CVSS version (CVSS): 4.0
Attack Vector (AV): Network (N)
Attack Complexity (AC): Low (L)
Attack Requirement (AT): Present (P)
Privileges Required (PR): None (N)
User Interaction (UI): Passive (P)
Vulnerable System Impact Confidentiality (VC): Low (L)
Vulnerable System Impact Integrity (VI): Low (L)
Vulnerable System Impact Availability (VA): None (N)
Subsequent System Impact Confidentiality (SC): Low (L)
Subsequent System Impact Integrity (SI): High (H)
Subsequent System Impact Availability (SA): None (N)
Modified Attack Vector (MAV): Network (N)
Modified Attack Complexity (MAC): Low (L)
Modified Attack Requirement (MAT): Present (P)
Modified Privileges Required (MPR): None (N)
Modified User Interaction (MUI): Passive (P)
Modified Vulnerable System Impact Confidentiality (MVC): Low (L)
Modified Vulnerable System Impact Integrity (MVI): Low (L)
Modified Vulnerable System Impact Availability (MVA): None (N)
Modified Subsequent System Impact Confidentiality (MSC): Low (L)
Modified Subsequent System Impact Integrity (MSI): High (H)
Modified Subsequent System Impact Availability (MSA): Negligible (N)
Safety (S): Not Defined (X)
Automatable (AU): Not Defined (X)
Recovery (R): Not Defined (X)
Value Density (V): Not Defined (X)
Vulnerability Response Effort (RE): Not Defined (X)
Provider Urgency (U): Not Defined (X)
Confidentiality Req. (CR): Not Defined (X)
Integrity Req. (IR): Not Defined (X)
Availability Req. (AR): Not Defined (X)
Exploit Maturity (E): Not Defined (X)

updated 11 hours ago by @LeSuisse Activity log

Created suggestion 18 hours ago
@LeSuisse accepted 11 hours ago
@LeSuisse published on GitHub 11 hours ago

Process Compose: Browser DNS rebinding lets websites control local process-compose MCP tools

Process Compose is a scheduler and orchestrator for non-containerized applications. Prior to 1.120.0, the MCP SSE listener in src/mcp/server.go accepts browser-origin requests to /sse and the returned message endpoint without validating the Host header, validating the Origin header, or authenticating the caller. When MCP SSE is enabled, a malicious website can use DNS rebinding to reach the loopback listener and issue MCP requests. If expose_control_tools is enabled, the attacker can enumerate process state, read or search logs, truncate logs, and start, stop, restart, or scale local processes; configured user-defined tools can expose additional commands and output. The Gin REST API token middleware does not protect this separately started MCP listener. This issue is fixed in version 1.120.0.