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Medium severity · published Sep 22, 2026
CVE-2026-77267
mcp-atlassian has an incomplete SSRF remediation
6.5
CVSS
0.3%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N
Attack vector
Network
Complexity
Low
Privileges
Low
User interaction
None
Confidentiality
High
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 25% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
MC
mcp-atlassian · sooperset
< 0.22.0 · source: vendor
MA
Mcp Atlassian · Mcp-atlassian
before 0.22.0 · source: NVD
Affected product
MC
mcp-atlassian
sooperset
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-77267
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-77267
x_refsource_CONFIRM
https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-5wf4-jqxh-8gm3
x_refsource_MISC
https://github.com/sooperset/mcp-atlassian/pull/1448
x_refsource_MISC
https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460
x_refsource_MISC
https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0
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