{"schema":"threatline.record/2","record":{"id":"CVE-2026-57178","aliases":["GHSA-3c93-f73f-qc9h","PYSEC-2026-4165"],"summary":"social-auth-core: VK App backend accepts unsigned callback data when auth_key is missing","details":"### Impact\n\nThe `vk-app` backend accepted VK application callback data without verifying the callback signature when the `auth_key` parameter was omitted.\n\nApplications using this backend could treat unsigned attacker-controlled data as a verified VK identity. An attacker could choose callback fields such as `viewer_id`, `access_token`, `api_id`, and `api_result`, potentially allowing authentication as an arbitrary VK user ID.\n\nThe issue affects only applications using the `vk-app` backend.\n\n### Patches\n\nThe issue has been fixed by requiring `auth_key` to be present and valid before callback data is trusted.\n\nUsers should upgrade to a patched version.\n\nFix:\n\n* https://github.com/python-social-auth/social-core/pull/1811\n\n### Workarounds\n\nApplications that cannot upgrade immediately should disable the `vk-app` backend by removing `social_core.backends.vk.VKAppOAuth2` from `SOCIAL_AUTH_AUTHENTICATION_BACKENDS`.\n\nThere is no complete workaround while continuing to use the vulnerable backend.\n\n### Credits\n\nReported by @lalalala5678 through GitHub private vulnerability reporting.","categories":["Runtimes & languages"],"product":"social-auth-core","vendor":"python-social-auth","ecosystem":"pip","affected_ranges":[{"source":"GitHub Advisory Database","source_url":"https://github.com/advisories/GHSA-3c93-f73f-qc9h","source_modified_at":"2026-09-24T19:57:25Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"ecosystem":"pip","name":"social-auth-core"},"range":"< 5.0.0"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-57178","source_modified_at":"2026-09-28T17:34:38.454Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"social-core","vendor":"python-social-auth","versions":[{"status":"affected","version":"< 5.0.0"}],"defaultStatus":null},{"source":"OSV","source_url":"https://osv.dev/vulnerability/GHSA-3c93-f73f-qc9h","source_modified_at":"2026-10-01T17:55:50.908917537Z","fetched_at":"2026-10-23T18:48:36.087640Z","package":{"name":"social-auth-core","ecosystem":"PyPI","purl":"pkg:pypi/social-auth-core"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"5.0.0"}]}],"versions":["0.0.1","0.1.0","0.2.0","0.2.1","1.0.0","1.0.1","1.1.0","1.2.0","1.3.0","1.4.0","1.5.0","1.6.0","1.7.0","2.0.0","3.0.0","3.1.0","3.2.0","3.3.0","3.3.1","3.3.2","3.3.3","3.4.0","4.0.2","4.0.3","4.1.0","4.2.0","4.3.0","4.4.0","4.4.1","4.4.2","4.5.0","4.5.1","4.5.2","4.5.3","4.5.4","4.5.5","4.5.6","4.6.0","4.6.1","4.7.0","4.8.0","4.8.1","4.8.2","4.8.3","4.8.4","4.8.5","4.8.6","4.8.7","4.9.0","4.9.1"]}],"fixed_versions":[{"source":"GitHub Advisory Database","source_url":"https://github.com/advisories/GHSA-3c93-f73f-qc9h","source_modified_at":"2026-09-24T19:57:25Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"ecosystem":"pip","name":"social-auth-core"},"version":"5.0.0"},{"source":"OSV","source_url":"https://osv.dev/vulnerability/GHSA-3c93-f73f-qc9h","source_modified_at":"2026-10-01T17:55:50.908917537Z","fetched_at":"2026-10-23T18:48:36.087640Z","package":{"name":"social-auth-core","ecosystem":"PyPI","purl":"pkg:pypi/social-auth-core"},"version":"5.0.0"}],"cvss":7.4,"severity":"High","kev":{"listed":false},"epss":{"probability":0.0016,"percentile":0.04846,"score_date":"2026-10-23"},"published_at":"2026-09-24T17:25:47.225Z","modified_at":"2026-10-01T17:55:50.908917537Z","provenance":[{"source":"GitHub Advisory Database","url":"https://github.com/advisories/GHSA-3c93-f73f-qc9h","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-09-24T19:57:25Z"},{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-57178","fetched_at":"2026-10-23T18:45:31.882637Z","source_modified_at":"2026-09-28T17:34:38.454Z"},{"source":"OSV","url":"https://osv.dev/vulnerability/GHSA-3c93-f73f-qc9h","fetched_at":"2026-10-23T18:48:36.087640Z","source_modified_at":"2026-10-01T17:55:50.908917537Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-57178","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["GitHub Advisory Database","CVE List","OSV","EPSS"],"references":[{"source":"CVE List","url":"https://github.com/python-social-auth/social-core/security/advisories/GHSA-3c93-f73f-qc9h","tags":["x_refsource_CONFIRM"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-57178","source":"GitHub Advisory Database"},{"url":"https://github.com/python-social-auth/social-core/pull/1811","source":"GitHub Advisory Database"},{"url":"https://github.com/python-social-auth/social-core/commit/1bfacdd0379e5eb46e169a99ab648b835e9bb6a2","source":"GitHub Advisory Database"},{"url":"https://github.com/python-social-auth/social-core/releases/tag/5.0.0","source":"GitHub Advisory Database"},{"url":"https://github.com/advisories/GHSA-3c93-f73f-qc9h","source":"GitHub Advisory Database"}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","ssvc":{"exploitation":"none","automatable":"no","technical_impact":"total","assessed_at":"2026-09-28T17:34:29.013431Z"},"classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":"vendor and product","confidence":"heuristic","reviewed":false},"change_timestamp":"2026-10-01T17:55:50.908917537Z","content_hash":"270c1d0d398d4bbef124ccfb2ecb4ad2100ecf56ff8551f8474a79b3cafe36f6"}}