vulnerability / NVI-00015313 / Revision 1
MCP Atlassian: SSRF Protection Bypass
GitHub lists this reviewed advisory for mcp-atlassian. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
mcp-atlassian
source listed< 0.22.0
## Environment - Project: `sooperset/mcp-atlassian` - Affected function: `validate_url_for_ssrf()` - Affected path: header-based Jira/Confluence URL authentication flow - Tested endpoint: `POST /mcp` - Tested version: `2.14.5` ## Description The SSRF protection in `validate_url_for_ssrf()` can be bypassed with a URL containing a backslash before userinfo-like syntax. Affected code: ```python parsed = urlparse(url) hostname = parsed.hostname ... ip_error = _check_ip_address(hostname) ... dns_error = _check_dns_resolution(hostname) ``` Payload: ```text http://127.0.0.1:6666\@www.baidu.com ``` For this input, `urllib.parse.urlparse()` treats the hostname as: ```text www.baidu.com ``` Therefore, `validate_url_for_ssrf()` validates `www.baidu.com` instead of `127.0.0.1`. However, the downstream request made through the Atlassian client / `requests.Session` reaches the local service: ```text http://127.0.0.1:6666/%5C@www.baidu.com/rest/api/2/myself ``` This allows an attacker-controlled Jira URL to target loopback or internal services. ## Proof of Concept Start a local HTTP server: ```bash python3 -m http.server 6666 --bind 127.0.0.1 ``` Start `mcp-atlassian` with streama
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. GitHub Advisory Database
A fixed release is not deployment evidence.
Check current vendor support and compatibility. After making a change, verify the deployed build and relevant runtime conditions. Keep the evidence, owner and time. An updated lockfile alone does not prove what is running.
04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
05 / Provenance
Sources you can inspect
Each assertion retains its source. Mirrored records may repeat one underlying publisher; additional links are not independent corroboration.
- GHSA-hgcf-4mq8-5266 ↗
GitHub Advisory Database · vendor advisory
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Public revision history
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- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.