CVE-2026-77274CWE-918ssrf

CVE-2026-77274

High · published September 22, 2026

CVSS v3.1
8.2
EPSS
0%
Percentile
24.2
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, validate_url_for_ssrf has a backslash authority confusion because it interprets the authority differently from the Requests connection layer in the header-based Jira and Confluence URL authentication flow. A crafted URL can validate as an external hostname while the HTTP client connects to an internal host, permitting server-side requests to protected network resources. This issue is fixed in version 0.22.0.

The record
Technical detail
CVSS v3.1
8.2 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
CVSS v4.0
8.8 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:N/SC:N/SI:N/SA:N
EPSS
0.00324 · 24.2th 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-hgcf-4mq8-5266 · [email protected]https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-hgcf-4mq8-5266 · 134c704f-9b21-4f2e-91b3-4a467353bcc0
EPSS history
Timeline
  • 24 SEP 03:25Z
    EPSS moved — → 1%
    epss
  • 22 SEP 17:36Z
    MCP Atlassian: SSRF Protection Bypass
    cvelistv5