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Advisory record · GHSA-6cr4-ccf3-x7h4

MCP Atlassian: Arbitrary file read via confluence_upload_attachment allows exfiltration of server credentials

CVSS 7.7 HighEPSS 0.0044 · 38th percentile

Published by the GitHub Advisory Database at 22 Sept 2026, 20:35 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

PackageEcosystemAffectedFixed in
mcp-atlassianPyPI<0.22.00.22.0
Identifiers
GHSA-6cr4-ccf3-x7h4 · CVE-2026-77259 · PYSEC-2026-4086
Weakness (CWE)
CWE-22 · CWE-552
Tags
Published
22 Sept 2026
Updated
1 Oct 2026

Machine-written summary

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

The mcp-atlassian package is vulnerable in versions before 0.22.0, and the fix is in 0.22.0. The confluence_upload_attachment tool does not validate the file path it is given, so an authenticated MCP client with edit access to a Confluence page can read arbitrary files from the server and upload their contents as an attachment. This can expose runtime secrets such as API tokens. Upgrade to mcp-atlassian 0.22.0 or later.

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
7.7 High 3.1 CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N CNA (GitHub_M)
  • CISA KEV Not listed.
  • EPSS 0.0044, the 38th percentile, on 10 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

  1. 31 Oct 2026, 14:09 UTC First seen by agentprime
  2. 31 Oct 2026, 14:09 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.