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MCP Atlassian: Incomplete path traversal fix allows intra-CWD module overwrite and RCE (bypass of CVE-2026-27825)

Type: advisorySources: OSV

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.

Products
Not specified
Affected versions
Not specified
Fixed versions
Not specified
CVEs
CVE-2026-77271
Confirmed fixed CVEs
Not specified
Updated in this feed
4 Nov 2026, 05:00 UTC · Revision 1

Source evidence

MCP Atlassian: Incomplete path traversal fix allows intra-CWD module overwrite and RCE (bypass of CVE-2026-27825)

core-osv · Original source

Published 22 Sept 2026, 18:00 UTC

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.

osv:CVE-2026-77271
Complete source record
{
  "id": "a2b0798c1990eccd940ca2ef9653f5e37ba839f4b9530a9a1f8f00c1f11dba48",
  "url": "https://osv.dev/vulnerability/CVE-2026-77271",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "MCP Atlassian: Incomplete path traversal fix allows intra-CWD module overwrite and RCE (bypass of CVE-2026-27825)",
    "summary": "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.",
    "evidence": "osv:CVE-2026-77271",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-77271",
      "aliases": [
        "CVE-2026-77271",
        "GHSA-6vmq-24h2-pj7j",
        "PYSEC-2026-4087"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "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"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/sooperset/mcp-atlassian",
              "type": "GIT",
              "events": [
                {
                  "introduced": "0"
                },
                {
                  "fixed": "b041733473f95119dd539542a43c280737a8e460"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "0.22.0"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StringRangeExpression"
                  },
                  {
                    "range": [
                      {
                        "fixed": "b041733473f95119dd539542a43c280737a8e460"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  },
                  {
                    "range": [
                      {
                        "fixed": "b041733473f95119dd539542a43c280737a8e460"
                      }
                    ],
                    "source": "REFERENCES_TAG",
                    "original_tag": "v0.22.0"
                  },
                  {
                    "cpe": "cpe:2.3:a:mcp-atlassian:mcp_atlassian:*:*:*:*:*:*:*:*",
                    "range": [
                      {
                        "introduced": "0"
                      },
                      {
                        "fixed": "0.22.0"
                      }
                    ],
                    "source": "CPE_RANGE"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v0.21.1",
            "v0.21.0",
            "v0.20.1",
            "v0.20.0",
            "v0.19.0",
            "v0.18.1",
            "v0.18.0",
            "v0.17.0",
            "v0.16.1",
            "v0.16.0",
            "v0.15.0",
            "v0.14.3",
            "v0.14.2",
            "v0.14.1",
            "v0.14.0",
            "v0.13.1",
            "v0.13.0",
            "v0.12.0",
            "v0.11.12",
            "v0.11.11",
            "v0.11.10",
            "v0.11.9",
            "v0.11.8",
            "v0.11.7",
            "v0.11.6",
            "v0.11.5",
            "v0.11.4",
            "v0.11.3",
            "v0.11.2",
            "v0.11.1",
            "v0.11.0",
            "v0.10.6",
            "v0.10.5",
            "v0.10.4",
            "v0.10.3",
            "v0.10.2",
            "v0.10.1",
            "v0.10.0",
            "v0.9.0",
            "v0.8.4",
            "v0.8.3",
            "v0.8.2",
            "v0.8.1",
            "v0.8.0",
            "v0.7.1",
            "v0.7.0",
            "v0.6.5",
            "v0.6.4",
            "v0.6.3",
            "v0.6.2",
            "v0.6.1",
            "v0.6.0",
            "v0.5.0",
            "v0.4.0",
            "v0.3.1",
            "v0.3.0",
            "v0.2.6",
            "v0.2.5",
            "v0.2.4",
            "v0.2.3",
            "v0.2.2",
            "v0.2.1",
            "v0.2.0",
            "v0.1.16",
            "v0.1.15",
            "v0.1.14",
            "v0.1.13",
            "v0.1.12",
            "v0.1.11",
            "v0.1.10",
            "v0.1.8",
            "v0.1.7",
            "v0.1.6",
            "v0.1.5",
            "v0.1.4"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-77271.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:33.521033931Z",
      "provider": "osv",
      "references": [
        "https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/77xxx/CVE-2026-77271.json",
        "https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-6vmq-24h2-pj7j",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-77271",
        "https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460",
        "https://github.com/sooperset/mcp-atlassian/pull/1448"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-22",
          "CWE-94"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/77xxx/CVE-2026-77271.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-77271",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 500424,
  "published_at": "2026-09-22T18:00:33.694+00:00"
}