Medium 5.9Published Sep 22, 2026

CVE-2026-77265MCP Atlassian: SSRF via DNS Rebinding in Header-Based Authentication Flow

Updated under an hour ago (Oct 26, 2026, 3:50 PM ET)

This data is behind schedule: last updated Oct 26, 2026, 3:50 PM ET. We are working on it.Behind: CVE records (cvelistV5).

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It affects sooperset mcp-atlassian and 1 other product. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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Every CVE for sooperset mcp-atlassian

Exploited in the last 30 days

MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, header-supplied Jira or Confluence URLs are resolved and validated before the HTTP client resolves the hostname again for the connection. An unauthenticated caller can use a DNS-rebinding hostname that returns a public address during validation and an internal address during connection, causing requests to internal or metadata services. The advisory traces the vulnerable input and processing flow through X-Atlassian-Jira-Url, X-Atlassian-Confluence-Url, validate_url_for_ssrf, and DNS rebinding, which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0.

CVSS: 5.9 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N
Weakness (CWE): CWE-918
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Analyzed
Record last updated: Sep 28, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

sooperset mcp-atlassian sooperset:mcp_atlassian (from the name)	before 0.22.0	CNA record
mcp-atlassian mcp_atlassian mcp-atlassian:mcp_atlassian	before 0.22.0	NVD

References

References

https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-49xv-9743-pw8w	x-refsource-confirm, exploit, vendor-advisory
https://github.com/sooperset/mcp-atlassian/pull/1448	x-refsource-misc, issue-tracking, patch
https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460	x-refsource-misc, patch
https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0	x-refsource-misc, release-notes

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.