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CVE-2026-73302

Authentication Bypass in @budibase/server (CVE-2026-73302)

Summary

Authentication bypass in @budibase/server (CVE-2026-73302). Risk of unauthorized operations or information disclosure. Exploitable via POST /realms/budi/protocol/openid-connect/token.

Original description

The description as published by the source.

Summary

Budibase's OIDC SSO login links an incoming SSO identity to an existing Budibase account by email address alone, without ever checking the email_verified claim of the OIDC ID token. Budibase first tries to match the IdP sub; when that misses (any fresh attacker IdP account) it silently falls back to matching by the email claim and merges into the existing account by email, preserving that account's _id and roles. Because the email_verified flag is never read, an attacker who can make a configured/trusted IdP emit a token carrying email = with email_verified = false is logged into Budibase as the victim, inheriting the victim's roles (including global admin/builder). Per OIDC Core §5.7 the email claim MUST NOT be used as an identity key unless email_verified is true; Budibase effectively delegates all account-linking trust to every configured IdP's email-verification policy while checking nothing itself. Full account takeover of any existing Budibase user, including the instance owner.

Details

The OIDC verify callback extracts the email and never consults email_verified:

  • packages/backend-core/src/middleware/passport/sso/oidc.ts:59 — email: getEmail(profile, jwtClaims).
  • getEmail (oidc.ts:113-135) returns profile._json.email ->jwtClaims.email -> preferred_username. No email_verified check.
  • buildJwtClaims (oidc.ts:99-107) assembles claims from _json.email/emails[0].value — no verification fl…

Source: GitHub Security Advisories (Global) NVD GitHub Advisory

Auto-generated summary

Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.

A vulnerability tracked as CVE-2026-73302 has been found in @budibase/server.
Attackers can target a specific entry point like POST /realms/budi/protocol/openid-connect/token over the network to misuse the product.
Risk of unauthorized operations or information disclosure.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "@budibase/server CVE-2026-73302" on the vendor's site.

CVE-2026-73302 (@budibase/server) — CWE-287
Attack surface: POST /realms/budi/protocol/openid-connect/token / GET /api/global/auth/default/oidc/configs/kc-oidc-1 / GET /api/global/auth/oidc/callback / GET /api/global/self
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

Authentication bypass (CWE-287) exists in @budibase/server. Attackers reach the vulnerable code path via POST /realms/budi/protocol/openid-connect/token.

📍 Affected scope

Check the vendor advisory for the affected versions of @budibase/server. Attack surface: POST /realms/budi/protocol/openid-connect/token / GET /api/global/auth/default/oidc/configs/kc-oidc-1 / GET /api/global/auth/oidc/callback / GET /api/global/self.

🔥 Severity

Severity: ?. Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to the patched release per vendor advisory.

🛡️ 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 /realms/budi/protocol/openid-connect/token requests with malformed payloads or SQL meta-characters. Run grep -r '@budibase/server' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

  1. 1
    Identify exposure identify 
    grep -r '@budibase/server' . | 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 @budibase/server を grep し、稼働しているサービス・バージョンを把握する。

  2. 2
    Hunt for indicators of compromise detect 
    grep 'POST /realms/budi/protocol/openid-connect/token' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'

    アクセスログで POST /realms/budi/protocol/openid-connect/token 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。

  3. 3
    Post-deployment verification verify 
    Replay attack against POST /realms/budi/protocol/openid-connect/token 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 2 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 @budibase/server
[{"type":"SEMVER","events":[{"introduced":"0"},{"last_affected":"3.38.1"}]}]

References

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