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CVE-2026-77267: MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira)

34
Routine
MEDIUM 6.5UPGRADE

CVE-2026-77267 is a medium-severity flaw (CVSS 6.5) affecting mcp atlassian. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, the X-Atlassian-Jira-Url and X-Atlassian-Confluence-Url headers are processed by _process_authentication_headers and used to construct Atlassian fetchers without calling validate_url_for_ssrf. A caller who can set these headers can supply an internal or metadata-service URL and cause the server to send requests to that destination

Why this priority

  • Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score6.5 (Medium)
Attack vectorNetwork (remote)
Attack complexityLow
Privileges neededLow
User interactionNone
EPSS exploit chance0.3% (top 75%)
CISA exploited listNo
WeaknessCWE-918
Published2026-09-22
Last modified2026-09-29
Publisher (CNA): GitHub, Inc. · Vendor: mcp-atlassian

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Last updated 2026-09-29 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

mcp-atlassian mcp atlassian UPGRADE
Affected: < 0.22.0
Fixed in: 0.22.0
Safe to downgrade to: no unaffected older release
1. Check installed version
apt-cache policy mcp-atlassian || rpm -q mcp-atlassian || mcp-atlassian --version
2. UPGRADE to 0.22.0 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade mcp-atlassian
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade mcp-atlassian
Note
Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.
Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-77267?

mcp atlassian: upgrade to 0.22.0. Exact commands for each OS are on this page.

Is CVE-2026-77267 being exploited?

CVE-2026-77267 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-77267 affect?

CVE-2026-77267 affects mcp atlassian. Severity is medium (CVSS 6.5). MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, the X-Atlassian-Jira-Url and X-Atlassian-Confluence-Url headers are processed by _process_authentication_headers and used

How urgent is CVE-2026-77267?

Priority 34/100. Public exploit reference

Software pages

Atlassian Confluence vulnerabilities · Atlassian Jira vulnerabilities

Related CVEs

References

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