CVE-2026-77253
MCP Atlassian: Jira and Confluence attachment upload tools can read arbitrary server-local files
Description
MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, Jira and Confluence attachment upload tools accept arbitrary local filesystem paths and send the selected bytes to Atlassian. In HTTP or multi-user deployments, a caller can cross the client-to-server filesystem boundary and disclose configuration, credentials, mounted secrets, or other files readable by the MCP process. The advisory traces the vulnerable input and processing flow through jira_upload_attachment, confluence_upload_attachment, file_path, and server-local filesystem, which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0.
INFO
Published Date :
Sept. 22, 2026, 7:16 p.m.
Last Modified :
Sept. 28, 2026, 1:23 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-77253
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | HIGH | [email protected] |
Solution
- Update MCP Atlassian server to version 0.22.0.
- Apply vendor patches for Jira and Confluence.
- Review access controls for attachment uploads.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-77253.
| URL | Resource |
|---|---|
| https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460 | Patch |
| https://github.com/sooperset/mcp-atlassian/pull/1448 | Issue Tracking Patch |
| https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0 | Release Notes |
| https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-vc25-24vv-fxxm | Exploit Vendor Advisory |
| https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-vc25-24vv-fxxm | Exploit Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-77253 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-77253
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-77253 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-77253 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Sep. 28, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:mcp-atlassian:mcp_atlassian:*:*:*:*:*:*:*:* versions up to (excluding) 0.22.0 Added Reference Type GitHub, Inc.: https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460 Types: Patch Added Reference Type GitHub, Inc.: https://github.com/sooperset/mcp-atlassian/pull/1448 Types: Issue Tracking, Patch Added Reference Type GitHub, Inc.: https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0 Types: Release Notes Added Reference Type CISA-ADP: https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-vc25-24vv-fxxm Types: Exploit, Vendor Advisory Added Reference Type GitHub, Inc.: https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-vc25-24vv-fxxm Types: Exploit, Vendor Advisory -
New CVE Received by [email protected]
Sep. 22, 2026
Action Type Old Value New Value Added Description MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, Jira and Confluence attachment upload tools accept arbitrary local filesystem paths and send the selected bytes to Atlassian. In HTTP or multi-user deployments, a caller can cross the client-to-server filesystem boundary and disclose configuration, credentials, mounted secrets, or other files readable by the MCP process. The advisory traces the vulnerable input and processing flow through jira_upload_attachment, confluence_upload_attachment, file_path, and server-local filesystem, which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0. Added CVSS V3.1 AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:L/A:N Added CWE CWE-22 Added Affected New affected value received. <a href="https://github.com/CVEProject/cvelistV5/blob/main/cves/2026/77xxx/CVE-2026-77253.json">CVE-2026-77253</a> Added Reference https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460 Added Reference https://github.com/sooperset/mcp-atlassian/pull/1448 Added Reference https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0 Added Reference https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-vc25-24vv-fxxm -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Sep. 22, 2026
Action Type Old Value New Value Added Reference https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-vc25-24vv-fxxm Added SSVC {'id': 'CVE-2026-77253', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'poc'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-09-22T18:49:32.148227Z'}