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Medium severity · published Sep 22, 2026
CVE-2026-77249
MCP Atlassian: Incomplete fix for CVE-2026-27826: redirect-based SSRF via unhooked requests session in Jira user-permission lookup
5.3
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, JiraUserMixin._lookup_user_by_permissions uses the module-level requests.get function instead of the fetcher's protected session. A caller-controlled public Jira URL can redirect that unhooked request to an internal address, bypassing the redirect checks added for CVE-2026-27826. The advisory traces the vulnerable input and processing flow through JiraUserMixin._lookup_user_by_permissions, requests.get, self.jira._session.get, and _make_ssrf_safe_hook, which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
Low
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 27% 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-2026-77249
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-77249
Patch
https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460
Issue Tracking
https://github.com/sooperset/mcp-atlassian/pull/1448
Release Notes
https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0
Exploit
https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-v9m3-wfh8-5646
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