Process Compose: Browser DNS rebinding lets websites control local process-compose MCP tools
CVSS score
5.1
EPSS probability
%0.3
Risk score
0.0
Published
1 mo ago
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Vulnerability description
DayBreach CVE AI Research
CVE-2026-77339 has vendor, distribution, patch and security-source records on file. We can compare them and prepare an explanation linked to the evidence.
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.
IMPACT: Affected Products and Software
Affected Products
The following products are affected by CVE-2026-77339 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.
RED HAT CSAF/VEX: Product Impact Check
SCORING: CVSS from Multiple Sources
CVSS Scores
The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.
| SCORE | VERSION | SEVERITY | VECTOR | SOURCE |
|---|---|---|---|---|
| 5.1 | CVSS 4.0 | — | Vector not published | GitHub Advisory |
| 5.1 | CVSS V40 | MEDIUM | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X | NVD |
| 5.1 | CVSS V4_0 | MEDIUM | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:H/SA:N | CVE CNA |
Patch and Remediation Guide
Solution & Remediation Advisory
1 doğrulanmış yama veya düzeltilmiş sürüm kanıtı bulundu.
1.120.0GitLab Advisory düzeltilmiş sürüm: 1.120.0
Upgrade to version 1.120.0 or above.
Upgrade to version 1.120.0 or above.
Public exploit and active exploitation status
Verified exploit intelligence
No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.
Weakness Classification and Attack Patterns (CWE & CAPEC)
CWE - Common Weakness Enumeration
While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-77339 is associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-77339 weaknesses.
Attack Vector and Accessibility
Official Sources and Advisories
Similar Vulnerabilities
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