CVE-2026-57178

social-auth-core: VK App backend accepts unsigned callback data when auth_key is missing

Published Sep 24, 2026 CVSS 3.1 · 7.4 High EPSS < 1% KEV · Not listed
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.

Remediation

No solution or workaround provided in the CVE record

Tracking

Sign in to view the affected projects.

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
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

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
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'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Sep 28, 2026, 5:34 PM
Reserved
Jun 24, 2026, 1:47 AM
Status
Awaiting Analysis
Published
Sep 24, 2026, 6:17 PM
Modified
Sep 28, 2026, 6:17 PM
Severity
Important
Public date
Sep 24, 2026, 5:25 PM