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MCP Atlassian: SSRF redirect protection missing for basic-auth and OAuth authentication branches

Type: advisorySources: OSV

MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, _make_ssrf_safe_hook is omitted from JiraFetcher and ConfluenceFetcher sessions created through the basic-auth and oauth_pat branches. If an attacker-controlled or compromised configured Atlassian instance returns a redirect to an internal address, those sessions can follow the redirect without revalidating its destination. This issue is fixed in version 0.22.0.

Products
Not specified
Affected versions
Not specified
Fixed versions
Not specified
CVEs
CVE-2026-77261
Confirmed fixed CVEs
Not specified
Updated in this feed
3 Nov 2026, 14:11 UTC · Revision 1

Source evidence

MCP Atlassian: SSRF redirect protection missing for basic-auth and OAuth authentication branches

core-osv · Original source

Published 22 Sept 2026, 18:06 UTC

MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, _make_ssrf_safe_hook is omitted from JiraFetcher and ConfluenceFetcher sessions created through the basic-auth and oauth_pat branches. If an attacker-controlled or compromised configured Atlassian instance returns a redirect to an internal address, those sessions can follow the redirect without revalidating its destination. This issue is fixed in version 0.22.0.

osv:CVE-2026-77261
Complete source record
{
  "id": "e151852ef7ecea78fe3b46b592eacbf8c8845e121be28b210914ff58cba415ec",
  "url": "https://osv.dev/vulnerability/CVE-2026-77261",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "MCP Atlassian: SSRF redirect protection missing for basic-auth and OAuth authentication branches",
    "summary": "MCP Atlassian is a Model Context Protocol (MCP) server for Atlassian products (Confluence and Jira). Prior to 0.22.0, _make_ssrf_safe_hook is omitted from JiraFetcher and ConfluenceFetcher sessions created through the basic-auth and oauth_pat branches. If an attacker-controlled or compromised configured Atlassian instance returns a redirect to an internal address, those sessions can follow the redirect without revalidating its destination. This issue is fixed in version 0.22.0.",
    "evidence": "osv:CVE-2026-77261",
    "products": [],
    "severity": "high",
    "structured": {
      "id": "CVE-2026-77261",
      "aliases": [
        "CVE-2026-77261",
        "GHSA-6529-c226-h328",
        "PYSEC-2026-4085"
      ],
      "metrics": [
        {
          "type": "CVSS_V3",
          "score": "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A: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-2026-77261.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:29.436599687Z",
      "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-2026-77261.json",
        "https://github.com/sooperset/mcp-atlassian/security/advisories/GHSA-6529-c226-h328",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-77261",
        "https://github.com/sooperset/mcp-atlassian/commit/b041733473f95119dd539542a43c280737a8e460",
        "https://github.com/sooperset/mcp-atlassian/pull/1448"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-918"
        ],
        "cna_assigner": "GitHub_M",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/77xxx/CVE-2026-77261.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-77261",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 496259,
  "published_at": "2026-09-22T18:06:20.64+00:00"
}