Security Digest · Vulnerability record
CVE-2026-53513: @better-auth/sso provider registration has server-side request forgery via unvalidated OIDC endpoints
Better Auth is an authentication and authorization library for TypeScript.
CVSS 9.6 Critical EPSS 0.2% · p15
Should you act?
Critical, preconditions apply
Severe if exploited, but exploitation needs conditions that may not apply to you. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 0.2%, percentile 15: FIRST’s model estimates a 0.2% chance of exploitation activity in the next 30 days, higher than 15% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Needs an account (low (any account)). Exposure depends on who can log in.
- Only applies if your dependency tree includes
@better-auth/sso(npm) >= 0.1.0, < 1.6.11, fixed in 1.6.11. Check your lockfile, including transitive dependencies.
What it is
Better Auth is an authentication and authorization library for TypeScript. Prior to 1.6.11, the @better-auth/sso plugin's POST /sso/register and POST /sso/update-provider endpoints accept attacker-controlled oidcConfig.userInfoEndpoint, tokenEndpoint, and jwksEndpoint URLs when skipDiscovery: true is set, store them on the ssoProvider row without origin validation, and fetch them during OIDC callback, allowing non-blind server-side request forgery and possible account linking when trustEmailVerified: true is configured. This issue is fixed in version 1.6.11.
From the GitHub advisory
Am I affected?
Users are affected if all of the following are true:
- Their application uses @better-auth/sso at a version >= 0.1.0,
For the non-blind SSRF impact (full IAM credential or internal HTTP body exfiltration), no further configuration is required.
For the account takeover escalation, additionally:
Weakness type: CWE-20, CWE-345, CWE-441, CWE-918.
Product: @better-auth/sso (npm) · Assigned by: GitHub_M · Published: 2026-07-15
Affected and fixed versions
| Ecosystem | Package | Vulnerable | First fixed |
|---|---|---|---|
| npm | @better-auth/sso | >= 0.1.0, < 1.6.11 | 1.6.11 |
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| better-auth | better-auth | >= 0.1.0, < 1.6.11 |
| @better-auth | sso | >= 0.1.0, < 1.6.11 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_M | 3.1 | 9.6 Critical | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N |
| GitHub | 3.1 | 9.6 | CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:N |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Privileges required: low (any account)
- User interaction: none
- Scope: changed (can affect other components)
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none, automatable no, technical impact total.
- FIRST EPSS (model of 2026-10-21): 0.25% probability of exploitation activity in the next 30 days; percentile 15.
Timeline
- — GitHub-reviewed advisory GHSA-5rr4-8452-hf4v published (critical)
- — CVE record last updated
- — CVE record published by GitHub_M
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vulnerability records
- GitHub Advisory GHSA-5rr4-8452-hf4v github.com
- CVE.org record CVE-2026-53513 cve.org
- NVD entry CVE-2026-53513 nvd.nist.gov
Other references from the CVE record and advisory
- github.com github.com
- github.com github.com
- github.com github.com
- github.com github.com