MCPA-2026-0029
mediumssrfCVSS 6.5
mcp-atlassian DNS-rebinding TOCTOU bypass of the SSRF fix
mcp-atlassian (PyPI) before 0.22.0 validates the attacker-controlled X-Atlassian-Jira-Url / X-Atlassian-Confluence-Url header host once at middleware time (the CVE-2026-27826 fix), but the outbound request is later built with the raw hostname and re-resolves at connect time with no IP pinning. A DNS-rebinding name that returns a public IP during validation and an internal IP at connect time bypasses the SSRF guard. Fixed in 0.22.0.
Affected packages
| Ecosystem | Package | Affected versions |
|---|---|---|
| pypi | mcp-atlassian | >= 0, < 0.22.0 |
Identifiers
GHSA-489g-7rxv-6c8qCWE-918
References
- advisory https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-489g-7rxv-6c8q
- web https://github.com/advisories/GHSA-489g-7rxv-6c8q
Timeline
- Published: 2026-07-10