Intel

CVE-2026-77250

mcp-atlassian: Cleartext Storage of Sensitive Information (CVE-2026-77250)

mediumEPSS 0.1%

Description

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.

Source: OSV (Open Source Vulnerabilities)NVD (NIST)GitHub Security Advisoriescvelistv5

Affected products

The following versions are affected. Older releases of the same product line are also vulnerable unless stated otherwise.

pypimcp-atlassian
0.10.00.10.10.10.20.10.30.10.40.10.50.10.60.1.10.1.100.11.00.1.110.11.10.11.100.11.110.11.120.1.120.11.20.11.2a20.1.130.11.30.1.140.11.40.1.150.11.50.1.160.11.60.11.70.11.80.11.90.1.20.12.00.1.30.13.00.13.10.1.40.14.00.14.10.14.20.14.30.15.00.1.60.16.00.16.10.1.70.17.00.1.80.18.00.18.1

Metrics

XIEM Effective CVSS
6.1
Source: cna-v3
EPSS percentile
1.1 %
Low — this CVE sits in the lower 10% of all CVEs scored today.
KEV status
—
Show all metrics
Severity
medium
Priority score
60.51
Exploit maturity
no public PoC known
CVSS v3
6.1
EPSS score
0.1 %
Low — model estimates < 1% exploitation likelihood.
Published
2026-10-01 16:38 UTC
CWE
CWE-312

Weakness classes (CWE)

  • CWE-312Base

    Cleartext Storage of Sensitive Information

    The product stores sensitive information in cleartext within a resource that might be accessible to another control sphere.

    cwe.mitre.org →

References & sources

Reanalysis & status changes

Chronological NVD audit events for this CVE — reanalyses, CVSS updates, CPE diffs.

  1. Initial Analysis2026-09-29 14:22 UTC· nvd@nist.gov
    • CPE Configuration: OR *cpe:2.3:a:mcp-atlassian:mcp_atlassian:*:*:*:*:*:*:*:* versions up to (excluding) 0.22.0
    • Reference Type: GitHub, Inc.: https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460 Types: Patch
    • Reference Type: GitHub, Inc.: https://github.com/sooperset/mcp-atlassian/pull/1448 Types: Issue Tracking, Patch
    • Reference Type: GitHub, Inc.: https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0 Types: Release Notes
  2. CVE Modified2026-09-22 19:16 UTC· 134c704f-9b21-4f2e-91b3-4a467353bcc0
    • Reference: https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-g5xv-mhgm-v5f6
    • SSVC: {"id":"CVE-2026-77250","role":"CISA Coordinator","options":[{"exploitation":"poc"},{"automatable":"no"},{"technicalIm…
  3. New CVE Received2026-09-22 18:17 UTC· security-advisories@github.com
    • Description: 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.
    • CVSS V3.1: AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N
    • CWE: CWE-312
    • Affected: New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/77xxx/CVE-2026-77250.json">CVE-2026-77250</a>