CVE-2026-77271CWE-22CWE-94path-traversalcode-injection

CVE-2026-77271

High · published September 22, 2026

CVSS v3.1
8.8
EPSS
1%
Percentile
44.0
In the wild
Unconfirmed
What it is

MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, validate_safe_path defaults its base directory to os.getcwd(), and affected Confluence attachment call sites omit base_dir, allowing attacker-selected writes within the working directory. This Python module overwrite can provide code execution when the application later imports the modified module, bypassing the remediation tracked as CVE-2026-27825. This issue is fixed in version 0.22.0.

The record
Technical detail
CVSS v3.1
8.8 · HIGH
Vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CVSS v4.0
8.3 · CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N
EPSS
0.00530 · 44.0th percentile
Weaknesses
CWE-22 · Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal'); CWE-94 · Improper Control of Generation of Code ('Code Injection')
Published
2026-09-22T22:17Z
Affected products (1)
ProductVersionsFixed in
mcp-atlassian/mcp_atlassian< 0.22.00.22.0
References (5)
https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460 · [email protected]https://github.com/sooperset/mcp-atlassian/pull/1448 · [email protected]https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0 · [email protected]https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-6vmq-24h2-pj7j · [email protected]https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-6vmq-24h2-pj7j · 134c704f-9b21-4f2e-91b3-4a467353bcc0
EPSS history
Timeline
  • 24 SEP 03:25Z
    EPSS moved — → 1%
    epss
  • 22 SEP 18:00Z
    MCP Atlassian: Incomplete path traversal fix allows intra-CWD module overwrite and RCE (bypass of CVE-2026-27825)
    cvelistv5