Python Social Auth is a social authentication/registration mechanism. Prior to version 5.0.0, the `vk-app` backend accepted VK application callback data without verifying the callback signature when the `auth_key` parameter was omitted. Applications 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. The issue affects only applications using the `vk-app` backend. The issue has been fixed in version 5.0.0 by requiring `auth_key` to be present and valid before callback data is trusted.
Advisories
Source ID Title
Github GHSA Github GHSA GHSA-3c93-f73f-qc9h social-auth-core: VK App backend accepts unsigned callback data when auth_key is missing
Fixes

Solution

No solution given by the vendor.


Workaround

No workaround given by the vendor.

History

Fri, 25 Sep 2026 14:45:00 +0000

Type Values Removed Values Added
First Time appeared Python-social-auth
Python-social-auth social-core
Vendors & Products Python-social-auth
Python-social-auth social-core

Fri, 25 Sep 2026 12:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

threat_severity

Important


Thu, 24 Sep 2026 17:30:00 +0000

Type Values Removed Values Added
Description Python Social Auth is a social authentication/registration mechanism. Prior to version 5.0.0, the `vk-app` backend accepted VK application callback data without verifying the callback signature when the `auth_key` parameter was omitted. Applications 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. The issue affects only applications using the `vk-app` backend. The issue has been fixed in version 5.0.0 by requiring `auth_key` to be present and valid before callback data is trusted.
Title social-auth-core: VK App backend accepts unsigned callback data when auth_key is missing
Weaknesses CWE-287
CWE-347
References
Metrics cvssV3_1

{'score': 7.4, 'vector': 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N'}


Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-09-24T17:25:47.225Z

Reserved: 2026-06-24T01:47:55.286Z

Link: CVE-2026-57178

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-09-24T18:17:14.970

Modified: 2026-09-25T13:27:31.790

Link: CVE-2026-57178

cve-icon Redhat

Severity : Important

Publid Date: 2026-09-24T17:25:47Z

Links: CVE-2026-57178 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-09-25T14:16:46Z

Weaknesses