CVE-2026-77249

MCP Atlassian: Incomplete fix for CVE-2026-27826: redirect-based SSRF via unhooked requests session in Jira user-permission lookup

Published: Sep 22, 2026Updated: Sep 23, 2026 Sources: CVE List NVDCWE-918

5.3MEDIUM

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.

No summary for this CVE yet.

CVSS Vector Breakdown

Exploitability

AV:NAttack Vector

Network

AC:LAttack Complexity

Low

PR:NPrivileges Required

None

UI:NUser Interaction

None

Scope

S:UScope

Unchanged

Impact

C:LConfidentiality

Low

I:NIntegrity

None

A:NAvailability

None

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Weaknesses

CWE-918

Affected Products

sooperset

commercialaka mcp atlassian

mcp-atlassianOn-prem

Enterprise Software / collaboration-groupware

Exploitability

No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.

Attack Graph

Products CVE Techniques Tactics

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MITRE ATT&CK

2 techniques

Command and Control

Initial Access

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References

https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-v9m3-wfh8-5646

github.com

https://github.com/sooperset/mcp-atlassian/pull/1448

github.com

https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460

github.com

and 1 more references View all →

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