CVE-2026-77274 MCP Atlassian - Server Side Request Forgery

MCP Atlassian < 0.22.0 contains a server-side request forgery caused by backslash authority confusion in validate_url_for_ssrf during header-based Jira and Confluence URL authentication, letting attackers access protected internal network resources, exploit requires crafted URL.

CVSS base score 8.2 /10
High
CISA KEV
Not listed
Public exploit
Proof of concept available
Authentication
Not required
EPSS
0.32% chance of exploitation in 30 days
View the NVD record ↗

Details

Type
Server Side Request Forgery
Impact
Server Side Request Forgery, Information Disclosure
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N
Published
22 September 2026
Updated
15 October 2026
Weakness
CWE-918

Vendor fix

Update to version 0.22.0 or later.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

References

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