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Advisory record · GHSA-7r34-79r5-rcc9

MCP Atlassian has SSRF via unvalidated X-Atlassian-Jira-Url / X-Atlassian-Confluence-Url headers

CVSS 8.2 HighCriticalEPSS 0.14 · 96th percentile

Critical, because:

  • CVSS score 8.2 (7.0 or more) and EPSS 0.14 (0.1 or more): a high score and a real chance of exploitation in the next 30 days.

How we decide what’s critical

Published by the GitHub Advisory Database at 10 Mar 2026, 18:48 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

PackageEcosystemAffectedFixed in
mcp-atlassianPyPI<0.17.00.17.0
Identifiers
GHSA-7r34-79r5-rcc9 · CVE-2026-27826 · PYSEC-2026-2621
Weakness (CWE)
CWE-918
Tags
Published
10 Mar 2026
Updated
13 Jul 2026

Machine-written summary

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

The mcp-atlassian package, versions before 0.17.0, is vulnerable to server-side request forgery in its HTTP deployment modes (streamable-http and sse). An unauthenticated attacker who can reach the HTTP endpoint can make the server send outbound requests to an arbitrary URL by supplying custom Jira or Confluence URL and personal token headers with no Authorization header. This can expose internal network resources and cloud instance metadata, and can inject attacker-controlled content into tool results. Upgrade to mcp-atlassian 0.17.0 or later.

Written 6 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
8.2 High 3.1 CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:L/A:N CNA (GitHub_M)
  • CISA KEV Not listed.
  • EPSS 0.14, the 96th percentile, on 15 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

  1. 31 Oct 2026, 14:59 UTC First seen by agentprime
  2. 31 Oct 2026, 14:59 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.