Vulnerability in lemonldap-ng (DEBIAN-CVE-2021-35473)

Summary

Vulnerability in lemonldap-ng (DEBIAN-CVE-2021-35473). Confidential information can be exposed externally. Mitigation: upgrade to 2.0.11+ds-4 or later.

Original description

The description as published by the source.

An issue was discovered in LemonLDAP::NG before 2.0.12. There is a missing expiration check in the OAuth2.0 handler, i.e., it does not verify access token validity. An attacker can use a expired access token from an OIDC client to access the OAuth2 handler The earliest affected version is 2.0.4.

Source: OSV.dev (Open Source Vulnerabilities) OSV

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 DEBIAN-CVE-2021-35473 has been found in lemonldap-ng.
Confidential information can be exposed externally.
What to do: upgrade lemonldap-ng to 2.0.11+ds-4 or later.
If unsure, ask your IT team or search "lemonldap-ng DEBIAN-CVE-2021-35473" on the vendor's site.

DEBIAN-CVE-2021-35473 (lemonldap-ng)
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Patched: 2.0.11+ds-4 — 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 (unclassified) exists in lemonldap-ng.

📍 Affected scope

Check the vendor advisory for the affected versions of lemonldap-ng.

🔥 Severity

Severity: ?. Confidential information can be exposed externally.

🔧 How to fix

Update to 2.0.11+ds-4.

🛡️ 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 request patterns matching this CVE's known IOCs. Run grep -r 'lemonldap-ng' . 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
Identify exposure identify
```
grep -r 'lemonldap-ng' . | 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 lemonldap-ng を grep し、稼働しているサービス・バージョンを把握する。
2
Apply patch patch
```
Upgrade lemonldap-ng to 2.0.11+ds-4
```
ステージング環境で 2.0.11+ds-4 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を含めること。
3
Post-deployment verification verify
```
Confirm patched version is live in production
```
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。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。

Affected packages

Debian:12 lemonldap-ng

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.0.11+ds-4"}]}]

Debian:13 lemonldap-ng

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.0.11+ds-4"}]}]

Debian:14 lemonldap-ng

[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2.0.11+ds-4"}]}]

References

advisory security-tracker.debian.org