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Advisory record · GHSA-6529-c226-h328

MCP Atlassian: SSRF redirect protection missing for basic-auth and OAuth authentication branches

CVSS 7.1 HighEPSS 0.0037 · 31st 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-6529-c226-h328 · CVE-2026-77261 · PYSEC-2026-4085
Weakness (CWE)
CWE-918
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.

GHSA-6529-c226-h328: mcp-atlassian versions before 0.22.0 do not apply the SSRF redirect protection under basic-auth and OAuth authentication. An attacker who controls the connected Atlassian server can return a redirect that makes the MCP server request internal addresses, such as cloud metadata endpoints, and read the responses. 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
7.1 High 3.1 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:N CNA (GitHub_M)
  • CISA KEV Not listed.
  • EPSS 0.0037, the 31st percentile, on 8 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.