Python Social Auth: OpenID Connect nonce is not bound to the browser session, so a stolen authorization code logs the attacker in as the victim

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

6.8 · CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N

EPSS

• CVE-2026-115910: 0.16% estimated exploitation activity in the next 30 days; percentile 4.84 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary The generic OpenID Connect backend (`OpenIdConnectAuth` and every backend built on it) stores the `nonce` in the shared Association table, not in the user's session. When the ID token comes back, `validate_claims` only checks that the nonce exists in that table and is not expired. It does not check that the nonce was issued to the browser that is finishing the login. So the nonce does not do its job. OIDC Core (section 15.5.2) and RFC 9700 (section 4.5) use the nonce to stop authorization code injection: an attacker who gets hold of a victim's unused authorization code should not be able to redeem it in the attacker's own browser. With social-auth-core, the attacker can. They start their own login to get a valid `state` for their session, then hit the callback with the victim's `code` and their own `state`. `state` passes because it belongs to the attacker's session, and the nonce in the victim's ID token passes because it is in the global table. The attacker's browser is…

Published by the source

28 Oct 2026, 21:16 UTC

Last modified by the source

28 Oct 2026, 21:30 UTC

Source last checked

29 Oct 2026, 06:10 UTC

1. Revision 2 · amended · 29 Oct 2026

   Amended from osv record GHSA-h2r5-x5m7-3935

2. Revision 1 · created · 28 Oct 2026

   Published from ghsa record GHSA-h2r5-x5m7-3935

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# Patch Next advisory brief: CVE-2026-115910

Advisory: Python Social Auth: OpenID Connect nonce is not bound to the browser session, so a stolen authorization code logs the attacker in as the victim
IDs: CVE-2026-115910, GHSA-h2r5-x5m7-3935
Record: https://patchnext.com/advisories/cve-2026-115910 (revision 2, source checked 29 Oct 2026, 06:10 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.8)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: social-auth-core 6.2.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- PyPI social-auth-core: affected < 6.2.0; fixed in 6.2.0

## Suggested inspection (read-only)
- `python -m pip show social-auth-core`: prints the installed version. Run with the environment that serves production active.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on social-auth-core.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://osv.dev/vulnerability/GHSA-h2r5-x5m7-3935 (OSV record GHSA-h2r5-x5m7-3935 lists affected ranges: PyPI social-auth-core >=0 <6.2.0 (fixed))
- Verified: https://github.com/advisories/GHSA-h2r5-x5m7-3935 (GitHub-reviewed advisory GHSA-h2r5-x5m7-3935 lists affected ranges: PyPI social-auth-core >=0 <=6.1.1)

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