Vulnerability-Lookup

CVE-2026-77259 (GCVE-0-2026-77259)

Vulnerability from cvelistv5 – Published: 2026-09-22 18:45 – Updated: 2026-09-22 18:45

Title

MCP Atlassian: Arbitrary file read via confluence_upload_attachment allows exfiltration of server credentials

Summary

MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, confluence_upload_attachment opens a caller-selected server-local file without checking that the resolved path remains in the workspace. A caller can upload environment files, credentials, or other readable host data to a Confluence page and retrieve it through Atlassian. The advisory traces the vulnerable input and processing flow through confluence_upload_attachment, file_path, and open(file_path, "rb"), which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0.

Severity

7.7 (High)


                        
                          CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N

CWE

CWE-22 - Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
CWE-552 - Files or Directories Accessible to External Parties

Assigner

GitHub_M mitre root

References

4 references

URL	Tags
https://github.com/sooperset/mcp-atlassian/securi…	x_refsource_CONFIRM
https://github.com/sooperset/mcp-atlassian/pull/1448	x_refsource_MISC
https://github.com/sooperset/mcp-atlassian/commit…	x_refsource_MISC
https://github.com/sooperset/mcp-atlassian/releas…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version	CPE status
sooperset	mcp-atlassian	Affected: < 0.22.0	guessed

Show details on NVD website

JSON

To clipboard

{
  "containers": {
    "cna": {
      "affected": [
        {
          "product": "mcp-atlassian",
          "vendor": "sooperset",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 0.22.0"
            }
          ]
        }
      ],
      "descriptions": [
        {
          "lang": "en",
          "value": "MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, confluence_upload_attachment opens a caller-selected server-local file without checking that the resolved path remains in the workspace. A caller can upload environment files, credentials, or other readable host data to a Confluence page and retrieve it through Atlassian. The advisory traces the vulnerable input and processing flow through confluence_upload_attachment, file_path, and open(file_path, \"rb\"), which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "attackComplexity": "LOW",
            "attackVector": "NETWORK",
            "availabilityImpact": "NONE",
            "baseScore": 7.7,
            "baseSeverity": "HIGH",
            "confidentialityImpact": "HIGH",
            "integrityImpact": "NONE",
            "privilegesRequired": "LOW",
            "scope": "CHANGED",
            "userInteraction": "NONE",
            "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N",
            "version": "3.1"
          }
        }
      ],
      "problemTypes": [
        {
          "descriptions": [
            {
              "cweId": "CWE-22",
              "description": "CWE-22: Improper Limitation of a Pathname to a Restricted Directory (\u0027Path Traversal\u0027)",
              "lang": "en",
              "type": "CWE"
            }
          ]
        },
        {
          "descriptions": [
            {
              "cweId": "CWE-552",
              "description": "CWE-552: Files or Directories Accessible to External Parties",
              "lang": "en",
              "type": "CWE"
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-09-22T18:45:48.269Z",
        "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "shortName": "GitHub_M"
      },
      "references": [
        {
          "name": "https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-6cr4-ccf3-x7h4",
          "tags": [
            "x_refsource_CONFIRM"
          ],
          "url": "https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-6cr4-ccf3-x7h4"
        },
        {
          "name": "https://github.com/sooperset/mcp-atlassian/pull/1448",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/sooperset/mcp-atlassian/pull/1448"
        },
        {
          "name": "https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460"
        },
        {
          "name": "https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0",
          "tags": [
            "x_refsource_MISC"
          ],
          "url": "https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0"
        }
      ],
      "source": {
        "advisory": "GHSA-6cr4-ccf3-x7h4",
        "discovery": "UNKNOWN"
      },
      "title": "MCP Atlassian: Arbitrary file read via confluence_upload_attachment allows exfiltration of server credentials"
    }
  },
  "cveMetadata": {
    "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
    "assignerShortName": "GitHub_M",
    "cveId": "CVE-2026-77259",
    "datePublished": "2026-09-22T18:45:48.269Z",
    "dateReserved": "2026-08-20T19:02:23.417Z",
    "dateUpdated": "2026-09-22T18:45:48.269Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-77259",
      "date": "2026-09-24",
      "epss": "0.00392",
      "percentile": "0.3057"
    },
    "nvd": {
      "cve": {
        "affected": [
          {
            "affectedData": [
              {
                "product": "mcp-atlassian",
                "vendor": "sooperset",
                "versions": [
                  {
                    "status": "affected",
                    "version": "\u003c 0.22.0"
                  }
                ]
              }
            ],
            "source": "security-advisories@github.com"
          }
        ],
        "cveTags": [],
        "descriptions": [
          {
            "lang": "en",
            "value": "MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, confluence_upload_attachment opens a caller-selected server-local file without checking that the resolved path remains in the workspace. A caller can upload environment files, credentials, or other readable host data to a Confluence page and retrieve it through Atlassian. The advisory traces the vulnerable input and processing flow through confluence_upload_attachment, file_path, and open(file_path, \"rb\"), which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0."
          }
        ],
        "id": "CVE-2026-77259",
        "lastModified": "2026-09-23T18:28:25.093",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "NETWORK",
                "availabilityImpact": "NONE",
                "baseScore": 7.7,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "NONE",
                "privilegesRequired": "LOW",
                "scope": "CHANGED",
                "userInteraction": "NONE",
                "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N",
                "version": "3.1"
              },
              "exploitabilityScore": 3.1,
              "impactScore": 4.0,
              "source": "security-advisories@github.com",
              "type": "Secondary"
            }
          ]
        },
        "published": "2026-09-22T19:16:50.327",
        "references": [
          {
            "source": "security-advisories@github.com",
            "url": "https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460"
          },
          {
            "source": "security-advisories@github.com",
            "url": "https://github.com/sooperset/mcp-atlassian/pull/1448"
          },
          {
            "source": "security-advisories@github.com",
            "url": "https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0"
          },
          {
            "source": "security-advisories@github.com",
            "url": "https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-6cr4-ccf3-x7h4"
          }
        ],
        "sourceIdentifier": "security-advisories@github.com",
        "vulnStatus": "Undergoing Analysis",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-22"
              },
              {
                "lang": "en",
                "value": "CWE-552"
              }
            ],
            "source": "security-advisories@github.com",
            "type": "Primary"
          }
        ]
      }
    }
  }
}

FKIE_CVE-2026-77259

Vulnerability from fkie_nvd - Published: 2026-09-22 19:16 - Updated: 2026-09-23 18:28

Severity

7.7 (High) - CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N

Summary

References

	URL	Tags
	security-advisories@github.com	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-6cr4-ccf3-x7h4

Impacted products

	Vendor	Product	Version

JSON

To clipboard

{
  "affected": [
    {
      "affectedData": [
        {
          "product": "mcp-atlassian",
          "vendor": "sooperset",
          "versions": [
            {
              "status": "affected",
              "version": "\u003c 0.22.0"
            }
          ]
        }
      ],
      "source": "security-advisories@github.com"
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, confluence_upload_attachment opens a caller-selected server-local file without checking that the resolved path remains in the workspace. A caller can upload environment files, credentials, or other readable host data to a Confluence page and retrieve it through Atlassian. The advisory traces the vulnerable input and processing flow through confluence_upload_attachment, file_path, and open(file_path, \"rb\"), which identify the affected entry points, controls, and code paths. This issue is fixed in version 0.22.0."
    }
  ],
  "id": "CVE-2026-77259",
  "lastModified": "2026-09-23T18:28:25.093",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 7.7,
          "baseSeverity": "HIGH",
          "confidentialityImpact": "HIGH",
          "integrityImpact": "NONE",
          "privilegesRequired": "LOW",
          "scope": "CHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 3.1,
        "impactScore": 4.0,
        "source": "security-advisories@github.com",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-09-22T19:16:50.327",
  "references": [
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/sooperset/mcp-atlassian/pull/1448"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0"
    },
    {
      "source": "security-advisories@github.com",
      "url": "https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-6cr4-ccf3-x7h4"
    }
  ],
  "sourceIdentifier": "security-advisories@github.com",
  "vulnStatus": "Undergoing Analysis",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-22"
        },
        {
          "lang": "en",
          "value": "CWE-552"
        }
      ],
      "source": "security-advisories@github.com",
      "type": "Primary"
    }
  ]
}

GHSA-6CR4-CCF3-X7H4

Vulnerability from github – Published: 2026-09-22 20:35 – Updated: 2026-09-22 20:35

Summary

MCP Atlassian: Arbitrary file read via confluence_upload_attachment allows exfiltration of server credentials

Details

Summary

Missing path validation in confluence_upload_attachment allows any authenticated MCP client to read arbitrary files from the server filesystem and exfiltrate their contents to Confluence. On Linux deployments, /proc/self/environ yields all runtime secrets in a single call.

Details

AttachmentsMixin.upload_attachment() in src/mcp_atlassian/confluence/attachments.py opens the caller-supplied file_path with no boundary check:

# line 477
files = {"file": (filename, open(file_path, "rb"))}

The download path was correctly hardened in GHSA-xjgw-4wvw-rgm4 via validate_safe_path() (lines 223, 272). That fix was not applied to the upload path, leaving it completely unguarded. The MCP tool layer (servers/confluence.py:1295) passes file_path verbatim with no additional sanitization.

PoC

# 1. Prepare target file (macOS demo; on Linux use /proc/self/environ directly)
cp ~/.aws/credentials /tmp/diagram.png

# 2. Call the MCP tool
confluence_upload_attachment(
    content_id = "<any page attacker can edit>",
    file_path  = "/tmp/diagram.png"
)

# 3. Download attachment from Confluence — contains raw credentials

Tested on mcp-atlassian 0.21.1 against live Confluence Cloud. Attachment confirmed uploaded and retrieved with full credential content intact.

Impact

Any MCP client with edit access to one Confluence page can read arbitrary files from the server process. On shared/Docker deployments, /proc/self/environ exposes all users' API tokens in a single request. Exfiltrated Atlassian tokens provide persistent API access independent of MCP, surviving server shutdown or patching.

Incomplete fix of GHSA-xjgw-4wvw-rgm4 — arbitrary file read on upload mirrors the arbitrary file write on download fixed in that advisory.

Suggested Fix

# src/mcp_atlassian/confluence/attachments.py — upload_attachment()
# Add after abspath conversion, before open():

try:
    validate_safe_path(file_path)
except ValueError as e:
    return {"success": False, "error": str(e)}

Same fix required in upload_attachments() and src/mcp_atlassian/jira/attachments.py.

Severity

7.7 (High)


                  
                    CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N

Show details on source website

JSON

To clipboard

{
  "affected": [
    {
      "package": {
        "ecosystem": "PyPI",
        "name": "mcp-atlassian"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.22.0"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-77259"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-22",
      "CWE-552"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-09-22T20:35:16Z",
    "nvd_published_at": null,
    "severity": "HIGH"
  },
  "details": "### Summary\n\nMissing path validation in `confluence_upload_attachment` allows any authenticated MCP client to read arbitrary files from the server filesystem and exfiltrate their contents to Confluence. On Linux deployments, `/proc/self/environ` yields all runtime secrets in a single call.\n\n---\n### Details\n\n`AttachmentsMixin.upload_attachment()` in `src/mcp_atlassian/confluence/attachments.py` opens the caller-supplied `file_path` with no boundary check:\n\n```python\n# line 477\nfiles = {\"file\": (filename, open(file_path, \"rb\"))}\n```\nThe download path was correctly hardened in GHSA-xjgw-4wvw-rgm4 via `validate_safe_path()` (lines 223, 272). That fix was not applied to the upload path, leaving it completely unguarded. The MCP tool layer (`servers/confluence.py:1295`) passes `file_path` verbatim with no additional sanitization.\n\n---\n### PoC\n\n```bash\n# 1. Prepare target file (macOS demo; on Linux use /proc/self/environ directly)\ncp ~/.aws/credentials /tmp/diagram.png\n\n# 2. Call the MCP tool\nconfluence_upload_attachment(\n    content_id = \"\u003cany page attacker can edit\u003e\",\n    file_path  = \"/tmp/diagram.png\"\n)\n\n# 3. Download attachment from Confluence \u2014 contains raw credentials\n```\nTested on mcp-atlassian 0.21.1 against live Confluence Cloud. Attachment confirmed uploaded and retrieved with full credential content intact.\n\n---\n### Impact\nAny MCP client with edit access to one Confluence page can read arbitrary files from the server process. On shared/Docker deployments, `/proc/self/environ` exposes all users\u0027 API tokens in a single request. Exfiltrated Atlassian tokens provide persistent API access independent of MCP, surviving server shutdown or patching.\n\nIncomplete fix of GHSA-xjgw-4wvw-rgm4 \u2014 arbitrary file read on upload mirrors the arbitrary file write on download fixed in that advisory.\n\n\n---\n### Suggested Fix\n\n```python\n# src/mcp_atlassian/confluence/attachments.py \u2014 upload_attachment()\n# Add after abspath conversion, before open():\n\ntry:\n    validate_safe_path(file_path)\nexcept ValueError as e:\n    return {\"success\": False, \"error\": str(e)}\n```\n\nSame fix required in `upload_attachments()` and `src/mcp_atlassian/jira/attachments.py`.",
  "id": "GHSA-6cr4-ccf3-x7h4",
  "modified": "2026-09-22T20:35:16Z",
  "published": "2026-09-22T20:35:16Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-6cr4-ccf3-x7h4"
    },
    {
      "type": "WEB",
      "url": "https://github.com/sooperset/mcp-atlassian/pull/1448"
    },
    {
      "type": "WEB",
      "url": "https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/sooperset/mcp-atlassian"
    },
    {
      "type": "WEB",
      "url": "https://github.com/sooperset/mcp-atlassian/releases/tag/v0.22.0"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:N/A:N",
      "type": "CVSS_V3"
    }
  ],
  "summary": "MCP Atlassian: Arbitrary file read via confluence_upload_attachment allows exfiltration of server credentials"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.

Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.

Action not permitted

CVE-2026-77259 (GCVE-0-2026-77259)

FKIE_CVE-2026-77259

GHSA-6CR4-CCF3-X7H4

Summary

Details

PoC

Impact

Suggested Fix

Tags

Sightings

Nomenclature

Related by attack behaviour