# CVE-2026-73683: Laravel Socialite Facebook Provider Authentication Bypass via Nonce Replay

Status: published. Published: 2026-08-14. Updated: 2026-11-08.

Laravel Socialite's Facebook provider contains an authentication bypass vulnerability that allows unauthenticated attackers to replay captured OIDC id_tokens by exploiting the missing nonce claim validation in the getUserByOIDCToken() function within FacebookProvider.php. Attackers who obtain a valid, unexpired id_token issued for the same Facebook App ID can submit the captured token to the backend userFromToken() endpoint, bypassing authentication controls because signature, aud, and iss checks pass while no session-bound nonce comparison is performed, resulting in unauthorized access to victim accounts.

## Remediation

- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: VulnCheck) — https://github.com/laravel/socialite/pull/789
- fix: The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches. (source: CNA: VulnCheck) — https://github.com/laravel/socialite/commit/caf714f55d51ab0d914b40033d8b0f489d6219cc

## Affected products and versions

- Laravel / Socialite: ≥ 0; < 5.29.0 (affected, semver). Source: CNA: VulnCheck

## Severity and prioritization

- CVSS 3.1: 8.1 (high); CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H; source: CNA: VulnCheck

- CVSS 4.0: 9.2 (critical); CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N; source: CNA: VulnCheck

- CISA KEV: No listing in collected sources

- EPSS: 0.76% as of 2026-11-08; percentile 55.54%

- SSVC: exploitation none; automatable no; technical impact total; source ADP: CISA-ADP

- Weaknesses: CWE-294

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/laravel/socialite/pull/789 (CNA: VulnCheck; product, patch)

- https://github.com/laravel/socialite/commit/caf714f55d51ab0d914b40033d8b0f489d6219cc (CNA: VulnCheck; patch)

- https://github.com/laravel/socialite (CNA: VulnCheck; vendor-advisory)

- https://www.vulncheck.com/advisories/laravel-socialite-facebook-provider-authentication-bypass-via-nonce-replay (CNA: VulnCheck; third-party-advisory)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-73683; retrieved 2026-11-08; source updated 2026-11-08

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2026-73683; retrieved 2026-11-08; source updated Not reported

Revision: 782f06b7161d6abe4c20a3995908d924fd82df3e846a7fd606c15e3994198e67

Canonical: https://y2.dev/cve/CVE-2026-73683

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