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CVE-2026-53515
high
CVSS 7.1
Privilege Escalation in @better-auth/sso (CVE-2026-53515)
Summary
vulnerability in @better-auth/sso (CVE-2026-53515). Data can be tampered with by attackers. Exploitable via `POST /sso/register`. Mitigation: upgrade to `1.6.11` or later.
AI summary snake-internal / snake-material-v2
A vulnerability tracked as **CVE-2026-53515** has been found in @better-auth/sso.
Attackers can target a specific entry point like `POST /sso/register` over the network to misuse the product.
Data can be tampered with by attackers. CVSS score: 7.1/10.
What to do: upgrade @better-auth/sso to **1.6.11** or later.
If unsure, ask your IT team or search "@better-auth/sso CVE-2026-53515" on the vendor's site.
CVE-2026-53515 (@better-auth/sso) — CWE-269 / CVSS v3 7.1
Attack vector: remote (network-reachable) / no user interaction
Attack surface: POST /sso/register / `next` / `providersLimit` / `organizationProvisioning.defaultRole`
Patched: `1.6.11` — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
❓ What is the problem
**A vulnerability** (CWE-269) exists in @better-auth/sso. Attackers reach the vulnerable code path via `POST /sso/register` without authentication.
📍 Affected scope
@better-auth/sso — . Attack surface: POST /sso/register / `next` / `providersLimit` / `organizationProvisioning.defaultRole`.
🔥 Severity
Severity: High (CVSS 7.1/10). Data can be tampered with by attackers
🔧 How to fix
Update to **1.6.11**.
🛡️ Workaround
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
🔍 Detection
Search webserver/proxy logs for unusual `POST /sso/register` requests with malformed payloads or SQL meta-characters. Run `grep -r '@better-auth/sso' .` against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response Actions (7 steps)
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
grep -r '@better-auth/sso' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で `@better-auth/sso` を grep し、稼働しているサービス・バージョンを把握する。
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3Hunt for indicators of compromise detect
grep 'POST /sso/register' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'アクセスログで `POST /sso/register` への異常なリクエスト (不正な認証ヘッダ・SQLメタ文字)を過去 30〜90日分捜索。WAF/SIEM があれば該当パスのアラート発火履歴を確認。
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6Apply patch patch
Upgrade @better-auth/sso to 1.6.11ステージング環境で 1.6.11 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスと、Step 3 で見つけた異常検知の続報チェックを含めること。
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7Post-deployment verification verify
Replay attack against POST /sso/register on staging to confirm patch closes the vectorパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番では Step 3 と同じログクエリでアラート再発が無いか継続監視。
Affected packages
npm
@better-auth/sso
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.6.11"}]}]