CVE-2026-77254 MCP Atlassian: Unauthenticated HTTP MCP requests can use globally configured Jira and Confluence credentials
Unauthenticated users can access Jira and Confluence tools using global operator credentials, allowing unauthorized data access and modification.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-77254?
CVE-2026-77254 is a critical missing authorization vulnerability in sooperset mcp-atlassian, published on 22 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, requests to the HTTP MCP endpoint without a per-user identity are allowed to reach tool handlers, which then use globally configured Jira or Confluence credentials. A network caller can perform operations with the operator account's permissions unless the deployment has an independent authentication boundary. The advisory traces the vulnerable input and processing flow through streamable-http, UserTokenMiddleware, _get_fetcher, and global credentials, which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0.
Weakness: CWE-306
Which versions are affected by CVE-2026-77254?
It affects 1 product.
Products include Mcp-Atlassian Mcp Atlassian.
How do I fix CVE-2026-77254?
No fix has been published for CVE-2026-77254 yet. Limit exposure of the affected software until one is available.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-77254 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-77254 exists.
Other vulnerabilities in sooperset mcp-atlassian
- CVE-2026-77244 [mcp-atlassian] Authentication bypass in HTTP transport: AtlassianOpaqueTokenVerifier accepts any non-empty token
- CVE-2026-27825 MCP Atlassian has an arbitrary file write leading to arbitrary code execution via unconstrained download_path in confluence_download_attachment
- CVE-2026-77243 MCP Atlassian: ENABLED_TOOLS / Toolset authorization bypass
- CVE-2026-77274 MCP Atlassian: SSRF Protection Bypass
- CVE-2026-77248 MCP Atlassian: Unauthenticated arbitrary local file read via upload_attachment file_path, chained with missing auth on streamable-http transport
Sources
Also known as GHSA-vc8m-84rp-53hx.