CVE-2026-77246
HIGHDescription
MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, an HTTP transport deployment with READ_ONLY_MODE=false accepts a request without an Authorization identity and permits attacker-controlled Atlassian service headers, including X-Atlassian-Confluence-Url, to select a public attacker hostname or one allowed by MCP_ALLOWED_URL_DOMAINS. A caller can then invoke confluence_upload_attachment or the Jira attachment variant in src/mcp_atlassian/jira/attachments.py with a server-local file_path and cause the MCP process to send the file to the selected attachment endpoint. This issue is fixed in version 0.22.0.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N
Exploit Intelligence
Low risk: more likely to be exploited than 35% of all known CVEs.
References
Related Vulnerabilities
Other CWE-22 (Path Traversal) vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2024-23897 | Critical | 9.8 | 100% | KEV + Ransom | Fix |
| CVE-2023-32315 | High | 8.6 | 100% | KEV | Fix |
| CVE-2022-29464 | Critical | 9.8 | 100% | KEV + Ransom | - |
| CVE-2021-26086 | Medium | 5.3 | 100% | KEV | Fix |
| CVE-2021-22005 | Critical | 9.8 | 100% | KEV + Ransom | Fix |
| CVE-2020-5902 | Critical | 9.8 | 100% | KEV + Ransom | Fix |
Common questions
How do I fix CVE-2026-77246?
Upgrade mcp atlassian to 0.22.0 or later.
Is CVE-2026-77246 being actively exploited?
Not that we know of. CVE-2026-77246 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.43% is the estimated probability that it will be exploited in the next 30 days. That is higher than 35% of all scored CVEs.
How severe is CVE-2026-77246?
CVE-2026-77246 has a CVSS v3 base score of 7.4, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2026-77246 affect?
Published advisories record a fix for mcp atlassian (NVD). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
Embed a live status badge for CVE-2026-77246
Markdown
[](https://tridentstack.com/cve/CVE-2026-77246)HTML
<a href="https://tridentstack.com/cve/CVE-2026-77246"><img src="https://tridentstack.com/cve/badge/CVE-2026-77246.svg" alt="CVE-2026-77246"></a>Find and fix vulnerabilities across your fleet
TridentStack Control continuously scans your Windows, macOS, and Linux fleet for known vulnerabilities, prioritizes them by severity and active exploitation, and patches them automatically.
This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-09-28.