CVE-2026-57178social-auth-core: VK App backend accepts unsigned callback data when auth_key is missing
Updated under an hour ago ()
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It affects python-social-auth social-core. Add what you run to find out whether that includes you.
No exploitation reported and no EPSS estimate yet.
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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.
- CVSS
- 7.4 HIGH (v3.1, CNA)CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
- Weakness (CWE)
- CWE-287, CWE-347
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- GitHub_M
- NVD analysis
- Awaiting Analysis
- Record last updated
- Sep 28, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
python-social-auth social-core python_social_auth:social_core (from the name) | before 5.0.0 | CNA record |
References
- https://github.com/python-social-auth/social-core/security/advisories/GHSA-3c93-f73f-qc9hx-refsource-confirm
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.