MSRXVulnerabilities / CVE-2026-77261
CVE-2026-77261
Published 2026-09-22 · Analyzed
CVE-2026-77261
MCP Atlassian: SSRF redirect protection missing for basic-auth and OAuth authentication branches
7.1 HIGH
CVSS 3.1 · CNA · github.com
CVSS 3.1 · CNA · github.com
0.4%
chance of exploitation in the next 30 days (EPSS; higher than 31% of CVEs)
chance of exploitation in the next 30 days (EPSS; higher than 31% of CVEs)
MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, _make_ssrf_safe_hook is omitted from JiraFetcher and ConfluenceFetcher sessions created through the basic-auth and oauth_pat branches. If an attacker-controlled or compromised configured Atlassian instance returns a redirect to an internal address, those sessions can follow the redirect without revalidating its destination. This issue is fixed in version 0.22.0.
Scores
Affected packages and fixed versions
| Package | Ecosystem | Fixed in |
|---|---|---|
| mcp-atlassian | PyPI | 0.22.0 |
Affected products
- mcp-atlassian mcp atlassian: < 0.22.0
Weakness: CWE-918
Also known as: GHSA-6529-c226-h328, PYSEC-2026-4085
4 references (advisories, patches, write-ups)
- https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460 · Patch
- https://github.com/sooperset/mcp-atlassian/pull/1448 · Patch
- https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0 · Release Notes
- https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-6529-c226-h328 · Exploit, Vendor Advisory
Sources: NVD, CVE.org, OSV.dev, FIRST EPSS. Missing ones did not answer or have no record yet.