Vulnerability in Python-Social-Auth Social-Core

CVE-2026-57179

Python Social Auth is a social authentication/registration mechanism. Prior to version 5.0.0, the partial-pipeline resume mechanism accepted `partial_token` as a bearer credential without binding it to the browser session that created it. Applications using resumable partial pipeline steps could allow an attacker to start an authentication flow, obtain a valid partial token and verification data, and cause a victim's browser to resume that attacker-controlled flow. This could authenticate the victim's browser as the attacker's account. The issue affects applications using partial pipeline steps such as `mail_validation` or custom steps decorated with `@partial`. The issue has been fixed in version 5.0.0 by binding partial pipeline resumes to the originating browser session.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 4.2 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:L/A:N.

EPSS exploit prediction

EPSS: 0.002 (5.0th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 5th percentile — 5.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2026-57179: held from 0.002 to 0.002.

EPSS over last 30 days · oldest: 0.002 · newest: 0.002 · change: 0.000

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2026-57179?
CVE-2026-57179 is a medium-severity vulnerability in Python-Social-Auth Social-Core, classified under Session Fixation. CVSS score: 4.2/10. Published 2026-09-24.
How severe is CVE-2026-57179?
Medium severity. CVSS v3 base score is 4.2 out of 10.