MCP Atlassian: Arbitrary File Read & Exfiltration (Confused Deputy) in JIRA update_issue

Date Sep 22, 2026

Type Vendor advisory

Signal High-risk advisory

Vendor / Product PyPI · mcp-atlassian

CVE CVE-2026-77255

High-risk advisory CVE-2026-77255

Summary

MCP Atlassian: Arbitrary File Read & Exfiltration (Confused Deputy) in JIRA update_issue

Why it matters

GitHub has published a reviewed security advisory for mcp-atlassian. Prioritize it with other application dependency updates.

Operator check

Check whether mcp-atlassian is present in application dependency manifests, lockfiles, or build images. Review the GitHub advisory and upgrade to a patched version where available.

Sources

GitHub Advisory GHSA-2xj6-xx86-cwwc NVD — CVE-2026-77255 Source reference

PatchBrief uses public sources. It does not scan environments, verify exposure, or replace vendor guidance.

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