{"id":"CVE-2026-55787","summary":"Flyto2 Core: SSRF guard bypass via IPv6 transition addresses (IPv4-mapped / 6to4 / NAT64) in validate_url_ssrf","details":"Flyto2 Core is an execution kernel for automation and AI-agent workflows. Prior to 2.26.3, validate_url_ssrf and is_private_ip in src/core/utils.py compare resolved addresses only against native private IPv4 and IPv6 ranges and do not unwrap IPv4-mapped, IPv4-compatible, 6to4, or NAT64 transition addresses. An authenticated workflow author can provide a transition-form literal URL through the Execution API POST /v1/execute route, http.get, or sibling guarded outbound-request modules, causing the guard to accept an address whose embedded IPv4 points to loopback, RFC 1918, or cloud metadata services. On a host that routes the selected transition form, the outbound request reaches the internal destination and returns the response body to the workflow caller, enabling read SSRF and disclosure of internal-service data or cloud credentials. This issue is fixed in version 2.26.3.","aliases":["GHSA-794r-5rp2-fpg8","PYSEC-2026-2481"],"modified":"2026-10-15T10:47:32.281437743Z","published":"2026-10-14T18:13:52.454Z","database_specific":{"cna_assigner":"GitHub_M","cwe_ids":["CWE-918"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55787.json"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/55xxx/CVE-2026-55787.json"},{"type":"FIX","url":"https://github.com/flytohub/flyto-core/commit/519e040384a74984848c4e84a6600e5f1020a6d2"},{"type":"FIX","url":"https://github.com/flytohub/flyto-core/pull/20"},{"type":"WEB","url":"https://github.com/flytohub/flyto-core/releases/tag/v2.26.3"},{"type":"ADVISORY","url":"https://github.com/flytohub/flyto-core/security/advisories/GHSA-794r-5rp2-fpg8"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-55787"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/flytohub/flyto-core","events":[{"introduced":"0"},{"fixed":"e8c6fd9902ff93389cd2e3ecaa472b7d91aec67e"}],"database_specific":{"source":"AFFECTED_FIELD","extracted_events":[{"introduced":"0"},{"fixed":"2.26.3"}]}}],"versions":["v2.26.0","v2.25.27","v2.17.6","v2.16.3","v2.5.0","v2.2.2"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-55787.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:N"}]}