Vulnerability in Supabase Auth
CVE-2026-31813
Supabase Auth is a JWT based API for managing users and issuing JWT tokens. Prior to 2.185.0, a vulnerability has been identified that allows an attacker to issue sessions for arbitrary users using specially crafted ID tokens when the Apple or Azure providers are enabled. The attacker issues a valid, asymmetrically signed ID token from their issuer for each victim email address, which then is sent to the Supabase Auth token endpoint using the ID token flow. If the ID token is OIDC compliant, the Auth server would validate it against the attacker-controlled issuer and link the existing OIDC identity (Apple or Azure) of the victim to an additional OIDC identity based on the ID token contents. The Auth server would then issue a valid user session (access and refresh tokens) at the AAL1 level to the attacker. This vulnerability is fixed in 2.185.0.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 4.8 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N.
EPSS exploit prediction
EPSS: 0.002 (11.0th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 11th percentile — 11.0% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.001 · newest: 0.002 · change: +0.001
Affected products
- Supabase Auth — versions < 2.185.0
Weakness classification (CWE)
References
- github.com/supabase/auth/security/advisories/GHSA-v36f-qvww-8w8m (Vendor Advisory)
Frequently asked questions
- What is CVE-2026-31813?
- CVE-2026-31813 is a medium-severity vulnerability in Supabase Auth, classified under Authentication Bypass by Spoofing. CVSS score: 4.8/10. Published 2026-03-11.
- How severe is CVE-2026-31813?
- Medium severity. CVSS v3 base score is 4.8 out of 10.