CVE-2026-73497 (GCVE-0-2026-73497)
Vulnerability from cvelistv5 – Published: 2026-09-14 19:50 – Updated: 2026-09-15 13:56
VLAI
EPSS
VEX
Title
MCP Atlassian is a Model Context Protocol (MCP): DNS-rebinding TOCTOU bypass of the SSRF fix (CVE-2026-27826): unauthenticated SSRF to cloud metadata
Summary
MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). From 0.17.0 until 0.22.0, validate_url_for_ssrf resolves the attacker-controlled X-Atlassian-Jira-Url and X-Atlassian-Confluence-Url header host once at middleware time, but the outbound request is built with the raw hostname and resolves it again at connection time with no IP pinning. An attacker-controlled DNS-rebinding name can return a public IP during validation and 169.254.169.254 or another internal IP during connection, enabling unauthenticated server-side requests to cloud metadata or internal services. The flaw spans src/mcp_atlassian/utils/urls.py, src/mcp_atlassian/servers/main.py, and src/mcp_atlassian/servers/dependencies.py; validate_url_for_ssrf returns only a verdict rather than a pinned IP, UserTokenMiddleware processes the attacker-controlled headers before fetcher creation, and the Jira and Confluence fetchers use the raw hostname. This issue is fixed in version 0.22.0.
Severity
6.5 (Medium)
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-15 13:25 UTC
CWE
- CWE-918 - Server-Side Request Forgery (SSRF)
Assigner
References
4 references
| URL | Tags |
|---|---|
| https://github.com/sooperset/mcp-atlassian/securi… | x_refsource_CONFIRM |
| https://github.com/sooperset/mcp-atlassian/pull/1448 | x_refsource_MISC |
| https://github.com/sooperset/mcp-atlassian/commit… | x_refsource_MISC |
| https://github.com/sooperset/mcp-atlassian/releas… | x_refsource_MISC |
Impacted products
1 product
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| sooperset | mcp-atlassian |
Affected:
>= 0.17.0, < 0.22.0
|
guessed |
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