{"id":"PYSEC-2026-4168","summary":"social-auth-core has a Session Fixation issue","details":"### Impact\n\nThe partial-pipeline resume mechanism accepted `partial_token` as a bearer credential without binding it to the browser session that created it.\n\nApplications using resumable partial pipeline steps could allow an attacker to start an authentication flow, obtain a valid partial token and verification data, and cause a victim's browser to resume that attacker-controlled flow. This could authenticate the victim's browser as the attacker's account.\n\nThe issue affects applications using partial pipeline steps such as `mail_validation` or custom steps decorated with `@partial`.\n\n### Patches\n\nThe issue has been fixed by binding partial pipeline resumes to the originating browser session.\n\nUsers should upgrade to a patched version.\n\nFix:\n\n* https://github.com/python-social-auth/social-core/pull/1816\n* https://github.com/python-social-auth/social-docs/pull/444\n* https://github.com/python-social-auth/social-app-django/pull/1009\n\n### Workarounds\n\nApplications that cannot upgrade immediately should disable resumable partial pipeline steps, including `mail_validation` and custom steps decorated with `@partial`.\n\nIf those flows are required, applications should avoid accepting partial resume links from untrusted contexts until a patched version can be deployed.\n\nThere is no complete workaround while continuing to use the vulnerable partial-pipeline resume mechanism.\n\n### Credits\n\nReported through GitHub private vulnerability reporting by Liyi Zhou, Ziyue Wang, Strick, Maurice, and Chenchen Yu from the University of Sydney security research team.\n\nReporter references:\n\n* https://lzhou1110.github.io/\n* https://zyy0530.github.io/\n* https://str1ckl4nd.github.io/\n* https://maurice.busystar.org/\n* https://7thparkk.github.io/","aliases":["CVE-2026-57179","GHSA-vqg6-3fw6-j9jg"],"modified":"2026-10-01T17:45:16.000899294Z","published":"2026-10-01T16:38:39.841686Z","references":[{"type":"WEB","url":"https://github.com/python-social-auth/social-core/security/advisories/GHSA-vqg6-3fw6-j9jg"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-57179"},{"type":"WEB","url":"https://github.com/python-social-auth/social-core/pull/1816"},{"type":"WEB","url":"https://github.com/python-social-auth/social-core/commit/0418782454ac7bbc6a9230ea21f7f5066fe89686"},{"type":"PACKAGE","url":"https://github.com/python-social-auth/social-core"},{"type":"WEB","url":"https://github.com/python-social-auth/social-core/releases/tag/5.0.0"},{"type":"PACKAGE","url":"https://pypi.org/project/social-auth-core"},{"type":"ADVISORY","url":"https://github.com/advisories/GHSA-vqg6-3fw6-j9jg"}],"affected":[{"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"],"database_specific":{"source":"https://github.com/pypa/advisory-database/blob/main/vulns/social-auth-core/PYSEC-2026-4168.yaml"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N"}]}