CVE-2026-77267CWE-918ssrf

CVE-2026-77267

Medium · published September 22, 2026

CVSS v3.1
6.5
EPSS
0%
Percentile
20.9
In the wild
Unconfirmed
What it is

MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, the X-Atlassian-Jira-Url and X-Atlassian-Confluence-Url headers are processed by _process_authentication_headers and used to construct Atlassian fetchers without calling validate_url_for_ssrf. A caller who can set these headers can supply an internal or metadata-service URL and cause the server to send requests to that destination, bypassing the incomplete CVE-2026-27826 remediation. This issue is fixed in version 0.22.0.

The record
Technical detail
CVSS v3.1
6.5 · MEDIUM
Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
CVSS v4.0
8.3 · CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N
EPSS
0.00294 · 20.9th percentile
Weakness
CWE-918 · Server-Side Request Forgery (SSRF)
Published
2026-09-22T22:17Z
Affected products (1)
ProductVersionsFixed in
mcp-atlassian/mcp_atlassian< 0.22.00.22.0
References (5)
https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460 · [email protected]https://github.com/sooperset/mcp-atlassian/pull/1448 · [email protected]https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0 · [email protected]https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-5wf4-jqxh-8gm3 · [email protected]https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-5wf4-jqxh-8gm3 · 134c704f-9b21-4f2e-91b3-4a467353bcc0
EPSS history
Timeline
  • 24 SEP 03:25Z
    EPSS moved — → 1%
    epss
  • 22 SEP 17:52Z
    mcp-atlassian has an incomplete SSRF remediation
    cvelistv5