Medium 5.9Published Sep 22, 2026

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

Updated under an hour ago (2026-10-19 11:10 UTC)

Does this affect you?

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.

Do this next

Start free and add your stack

Free account, 1 product

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

https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-49xv-9743-pw8wx-refsource-confirm, exploit, vendor-advisory
https://github.com/sooperset/mcp-atlassian/pull/1448x-refsource-misc, issue-tracking, patch
https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460x-refsource-misc, patch
https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0x-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.