CVE-2026-77250
MEDIUMDescription
MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, OAuthConfig writes a plaintext fallback file containing access and refresh tokens under the user's .mcp-atlassian directory using process-default permissions. On systems with a permissive umask, same-group or other local users and processes can read the persisted tokens and reuse the associated Atlassian access. The advisory traces the vulnerable input and processing flow through OAuthConfig._save_tokens, ~/.mcp-atlassian/oauth-<client_id>.json, access_token, and refresh_token, which identify the affected entry points, controls, and code paths. 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:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N
Exploit Intelligence
Low risk: more likely to be exploited than 1% of all known CVEs.
References
Related Vulnerabilities
Other CWE-312 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2023-50719 | High | 7.5 | 84% | - | Fix |
| CVE-2022-26148 | Critical | 9.8 | 53% | - | - |
| CVE-2020-24577 | High | 7.5 | 19% | - | Fix |
| CVE-2021-27140 | High | 7.5 | 19% | - | - |
| CVE-2021-27176 | High | 7.5 | 19% | - | - |
| CVE-2021-27174 | High | 7.5 | 19% | - | - |
Common questions
How do I fix CVE-2026-77250?
Upgrade mcp atlassian to 0.22.0 or later.
Is CVE-2026-77250 being actively exploited?
Not that we know of. CVE-2026-77250 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.11% is the estimated probability that it will be exploited in the next 30 days. That is higher than 1% of all scored CVEs.
How severe is CVE-2026-77250?
CVE-2026-77250 has a CVSS v3 base score of 6.1, rated medium. 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-2026-77250 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.
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Markdown
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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 2026-09-29.