Atlassian mcp-atlassian up to 0.21.x OAuth Token oauth-.json permission

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
4.3$0-$5k0.74+

Summaryinfo

A vulnerability was found in Atlassian mcp-atlassian up to 0.21.x and classified as problematic. This affects an unknown function of the file oauth-.json of the component OAuth Token Handler. The manipulation results in permission. This vulnerability is identified as CVE-2026-77268. The attack is only possible with local access. There is not any exploit available. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability classified as problematic has been found in Atlassian mcp-atlassian up to 0.21.x. Affected is an unknown code of the file oauth-.json of the component OAuth Token Handler. The manipulation with an unknown input leads to a permission vulnerability. CWE is classifying the issue as CWE-275. This is going to have an impact on confidentiality. CVE summarizes:

MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, the OAuth fallback token directory and JSON file are created without explicit owner-only modes. Local users or processes with access through the resulting group or world permission bits can read access and refresh tokens and reuse the associated Atlassian session. The advisory traces the vulnerable input and processing flow through ~/.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.

The advisory is shared for download at github.com. This vulnerability is traded as CVE-2026-77268 since 08/20/2026. The exploitability is told to be easy. The attack needs to be approached locally. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1222.

By approaching the search of inurl:oauth-.json it is possible to find vulnerable targets with Google Hacking.

Upgrading to version 0.22.0 eliminates this vulnerability.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.4
VulDB Meta Temp Score: 4.3

VulDB Base Score: 3.3
VulDB Temp Score: 3.2
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 5.5
CNA Vector (GitHub_M): 🔒

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Permission
CWE: CWE-275 / CWE-266
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: No

Availability: 🔒
Status: Not defined
Google Hack: 🔒
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: mcp-atlassian 0.22.0

Timelineinfo

08/20/2026 CVE reserved
09/22/2026 +33 days Advisory disclosed
09/22/2026 +0 days VulDB entry created
09/22/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: atlassian.com

Advisory: github.com
Status: Confirmed

CVE: CVE-2026-77268 (🔒)
GCVE (CVE): GCVE-0-2026-77268
GCVE (VulDB): GCVE-100-408636

Entryinfo

Created: 09/22/2026 21:10
Changes: 09/22/2026 21:10 (66)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

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