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Advisory record · GHSA-5gm3-9crp-6g3v

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

CVSS 5.1 MediumEPSS 0.0026 · 17th percentile

Published by the GitHub Advisory Database at 18 Sept 2026, 17:17 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

PackageEcosystemAffectedFixed in
github.com/f1bonacc1/process-composeGo<1.120.01.120.0
Identifiers
GHSA-5gm3-9crp-6g3v · CVE-2026-77339 · GO-2026-6515
Weakness (CWE)
CWE-306 · CWE-346
Tags
Published
18 Sept 2026
Updated
28 Sept 2026

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

Process Compose versions before 1.120.0 are vulnerable when MCP SSE is enabled. A malicious website can use DNS rebinding to send requests to the local MCP SSE listener from a victim's browser, without a token, cookie, or other credential. This can enumerate and control local processes and read their logs, including any secrets they print. Upgrade to Process Compose 1.120.0 or later. Leaving MCP SSE disabled also avoids the exposure.

Written 1 Nov 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

ScoreRatingCVSSVectorSource
5.1 Medium 4.0 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 CNA (GitHub_M)
  • CISA KEV Not listed.
  • EPSS 0.0026, the 17th percentile, on 6 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

  1. 31 Oct 2026, 14:12 UTC First seen by agentprime
  2. 31 Oct 2026, 14:12 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.