CVE-2026-77250

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.

Overview

State: PUBLISHED
Assigner (CNA): GitHub_M
CVSS severity: MEDIUM
CVSS score: 6.1 / 10
CVSS vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N
Effective score: 6.1 / 10 MEDIUM source: CNA overview
CWE(s): CWE-312
Reserved: 2026-08-20
Published: 2026-09-22 17:51 UTC
Last updated: 2026-09-22 18:42 UTC
Source: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/77xxx/CVE-2026-77250.json

NVD triage scoring NVD CVE 2.0

Layer NVD adds on top of the CNA's CVE record — published / last-modified timestamps, exploitability / impact subscores, and the FIRST.org EPSS probability that this CVE will be exploited in the wild in the next 30 days.

NVD published: 2026-09-22 18:17:17 UTC
NVD last modified: 2026-09-22 19:16:49 UTC
NVD CVSS v3.1: 6.1 / 10 MEDIUM source: security-advisories@github.com
NVD CVSS vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N
Exploitability subscore: 1.8 / 10
Impact subscore: 4.2 / 10

European Union Vulnerability Database ENISA EUVD

ENISA's official EU repository for curated vulnerability intelligence. Carries a separate identifier (EUVD-YYYY-NNNN) and frequently exposes an earlier-published description + CVSS than NVD does.

EUVD ID: EUVD-2026-84619
Assigner: GitHub_M
Published: Sep 22, 2026, 5:51:02 PM
Updated: Sep 22, 2026, 6:42:59 PM
EUVD base score (CVSS 3.1): 6.1 / 10
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N
EUVD-reported EPSS: 0.0000
Vendors: sooperset
Products: mcp-atlassian (< 0.22.0)
Aliases: GHSA-g5xv-mhgm-v5f6

ENISA 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.

EUVD references (4)

Affected products (1)

Vendor	Product	Versions	Platforms
sooperset	mcp-atlassian	`< 0.22.0` (affected)	—

Vendor references (4)

References embedded in the original CVE record by the assigning CNA.

https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-g5xv-mhgm-v5f6 x_refsource_CONFIRM
https://github.com/sooperset/mcp-atlassian/pull/1448 x_refsource_MISC
https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460 x_refsource_MISC
https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0 x_refsource_MISC

Web references (0)

DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.

No web references attached yet.

NVD-tagged references (5)

Reference list NVD curates from the CNA record, vendor advisories, and third-party reports. The tag chips below are NVD's analyst-assigned categories.

https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460 security-advisories@github.com
https://github.com/sooperset/mcp-atlassian/pull/1448 security-advisories@github.com
https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0 security-advisories@github.com
https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-g5xv-mhgm-v5f6 security-advisories@github.com
https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-g5xv-mhgm-v5f6 134c704f-9b21-4f2e-91b3-4a467353bcc0

Remediations (10)

July 2026 Critical Patch Update Released | security - Oracle Blogs

web:blogs.oracle.com

For more information about the Critical Patch Update program, see the security vulnerability remediation practices page located on the Oracle Trust Center.

2026-09-23 15:44 UTC
Security Update Guide - Microsoft

web:msrc.microsoft.com

The Microsoft Security Response Center (MSRC) investigates all reports of security vulnerabilities affecting Microsoft products and services, and provides the information here as part of the ongoing effort to help you manage security risks and help keep your systems protected.

2026-09-23 15:44 UTC
Microsoft Patch Tracker (September 2026): Exploit-Ranked | Senserva

web:senserva.com

Every Microsoft security patch (KB) and the CVEs it fixes, with severity, CVSS, and CISA KEV status. Cross-linked to the CVE reference.

2026-09-23 15:44 UTC
March 10, 2026—Hotpatch KB5079420 (OS Builds 26200.7979 and 26100.7979 ...

web:support.microsoft.com

This Hotpatch update for Windows 11, version 25H2 and 24H2 (KB5079420), improves functionality, performance, and reliability. To learn more about differences between security updates, optional non-security preview updates, out-of-band (OOB) updates, and continuous innovation, see Windows monthly updates explained. For information on Windows update terminology, see the different types of ...

2026-09-23 15:44 UTC
September 8, 2026—KB5122878 (OS Builds 19045.7725 and 19044.7725 ...

web:support.microsoft.com

This security update includes fixes and quality improvements that are part of the following updates: August 11, 2026—KB5120249 (OS Builds 19045.7663 and 19044.7663) The following is a summary of the issues that this update addresses when you install this update. If there are new features, it lists them as well. The bold text within the brackets indicates the item or area of the change we are ...

2026-09-23 15:44 UTC
SAP Security Patch Day - June 2026

web:support.sap.com

SAP security Patch Day Bulletin This post shares the information on security notes that remediate vulnerabilities discovered in SAP products. SAP strongly recommends that the customer visits the support portal and applies patches on priority to protect their SAP landscape. On 9th of June 2026 , SAP security patch day saw the release of 15 new security notes.

2026-09-23 15:44 UTC
Microsoft Patch Tuesday, July 2026 Security Update Review

web:threatprotect.qualys.com

Microsoft's July 2026 Patch Tuesday delivers security updates for a broad range of products and services, including several vulnerabilities that pose significant risks to enterprise environments.

2026-09-23 15:44 UTC
CVE-2026-77250 - MCP Atlassian Tokens Exposed Via Plaintext…

web:vulmon.com

Vulnerability Summary MCP Atlassian versions prior to 0.22.0 store access and refresh tokens in plaintext within the user's .mcp-atlassian directory. On systems with permissive umask settings, local users and processes can read these persisted tokens and reuse them to access Atlassian products. The vulnerability stems from the OAuthConfig._save_tokens function writing to the ~/.mcp-atlassian ...

2026-09-23 15:44 UTC
Oracle Critical Patch Update Advisory - April 2026

web:www.oracle.com

This Critical Patch Update contains 481 new security patches across the product families listed below. Please note that an MOS note summarizing the content of this Critical Patch Update and other Oracle Software Security Assurance activities is located at April 2026 Critical Patch Update: Executive Summary and Analysis.

2026-09-23 15:44 UTC
Oracle Critical Patch Update Advisory - July 2026

web:www.oracle.com

This Critical Patch Update contains 1448 new security patches across the product families listed below. Please note that a My Oracle Support (MOS) note summarizing the content of this Critical Patch Update and other Oracle Software Security Assurance activities is located at July 2026 Critical Patch Update: Executive Summary and Analysis.

2026-09-23 15:44 UTC

AI Forensic Analysis

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Raw JSON

The full cvelistV5 record. Download as CVE-2026-77250.json.

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