vulnerability / NVI-00012982 / Revision 3
social-auth-core: VK App backend accepts unsigned callback data when auth_key is missing
GitHub lists this reviewed advisory for social-auth-core. Published version ranges and source prerequisites are shown below; this is not an inspection of a visitor’s application.
This report has not inspected your inventory, configuration, deployed build, reachability or evidence. A catalog listing and a severity score do not establish exposure or compromise.
01 / Meaning
Why it matters
Published affected context helps an owner decide what evidence to gather. This report has not examined your application.
7.4 high
GitHub source severity; exploitability and local consequence require separate evidence.
As of · GitHub Advisory Database
7.4 HIGH (3.1)
security-advisories@github.com severity; no combined Null risk score.
0.160%
FIRST EPSS model v2026.06.15; exploitation probability over 30 days, percentile 0.05187. Missing scores are unknown.
As of · FIRST EPSS
02 / Applicability
The affected context
Affected versions, configuration prerequisites and known exclusions are public. Confirm each one against the deployed service.
social-auth-core
source listed< 5.0.0
### Impact 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. ### Patches The issue has been fixed by requiring `auth_key` to be present and valid before callback data is trusted. Users should upgrade to a patched version. Fix: * https://github.com/python-social-auth/social-core/pull/1811 ### Workarounds Applications that cannot upgrade immediately should disable the `vk-app` backend by removing `social_core.backends.vk.VKAppOAuth2` from `SOCIAL_AUTH_AUTHENTICATION_BACKENDS`. There is no complete workaround while continuing to use the vulnerable backend. ### Credits Reported by @lalalala5678 through GitHub private vulnerability reporting.
03 / Response
What to do next
- investigate
Identify the exact component and deployed version, examine the linked publisher’s conditions, and retain evidence of any mitigation.
Confirm current vendor support, compatibility and deployment evidence. This report has not tested a fix in your system. FIRST EPSS
A fixed release is not deployment evidence.
Check current vendor support and compatibility. After making a change, verify the deployed build and relevant runtime conditions. Keep the evidence, owner and time. An updated lockfile alone does not prove what is running.
04 / Limits
What this report cannot establish
- Customer inventory, deployment, reachability and exploitation have not been inspected.
- NVD lastModified does not establish freshness of every associated CPE record.
05 / Provenance
Sources you can inspect
Each assertion retains its source. Mirrored records may repeat one underlying publisher; additional links are not independent corroboration.
- GHSA-3c93-f73f-qc9h ↗
GitHub Advisory Database · vendor advisory
Observed . GitHub Advisory Database; CC-BY-4.0. Each advisory links its original attribution. Null normalizes fields.
- CVE-2026-57178 ↗
NIST National Vulnerability Database · official catalog
Observed . This product uses data from the NVD API but is not endorsed or certified by the NVD.
- CVE-2026-57178 ↗
FIRST EPSS · official catalog
Observed . FIRST EPSS; probability of exploitation in the next 30 days, not local compromise. Dataset date/model retained; FIRST services terms apply.
Public revision history
Only published revisions appear here. Routine fetches do not create a material-change event.
- Revision 3 ·
Source facts changed; compare the preserved prior revision.
- Revision 2 ·
Dated EPSS estimate updated; this is not a new disclosure or proof of exploitation.
- Revision 1 ·
First indexed by Null; source disclosure date is shown separately.