Vulnerability in lemur (CVE-2026-71308)
Summary
Vulnerability in lemur (CVE-2026-71308). Data can be tampered with by attackers. Exploitable via POST /api/1/certificates. Mitigation: upgrade to 1.9.3 or later.
Original description
The description as published by the source.
Summary
Repo under test: https://github.com/Netflix/lemur
The certificate create and upload endpoints accept a replaces[] (alias replacements) array that is resolved to live Certificate ORM objects with no ownership or CertificatePermission check on the referenced certificates. The SQLAlchemy Certificate.replaces append listener then immediately sets victim.notify = False and populates victim.replaced. From that point the victim certificate is excluded from auto-reissue, its expiration notifications are silenced, and the periodic certificate_rotate Celery task deploys the attacker's certificate (endpoint.certificate.replaced[0]) onto every endpoint serving the victim certificate.
Any authenticated non-read-only user can therefore silently substitute their own certificate onto production load balancers and Kubernetes secrets they hold no role on, while suppressing the legitimate certificate's lifecycle automation.
Affected route
POST /api/1/certificates
POST /api/1/certificates/upload
PUT /api/1/certificates/
Affected code
lemur/certificates/schemas.py:402—replaces = fields.Nested(AssociatedCertificateSchema, missing=[], many=True)accepted on create/upload/editlemur/schemas.py:152—AssociatedCertificateSchemaresolves any certificate by id/name via `fetch_objects(Certificate…
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-2026-71308 has been found in lemur.
Attackers can target a specific entry point like POST /api/1/certificates over the network to misuse the product.
Data can be tampered with by attackers. CVSS score: 8.1/10.
What to do: upgrade lemur to 1.9.3 or later.
If unsure, ask your IT team or search "lemur CVE-2026-71308" on the vendor's site.
CVE-2026-71308 (lemur) — CWE-639 / CVSS v3 8.1
Attack vector: remote (network-reachable) / no user interaction
Attack surface: POST /api/1/certificates / POST /api/1/certificates/upload / PUT /api/1/certificates/ / POST /certificates
Patched: 1.9.3 — 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.
A vulnerability (CWE-639) exists in lemur. Attackers reach the vulnerable code path via POST /api/1/certificates.
Check the vendor advisory for the affected versions of lemur. Attack surface: POST /api/1/certificates / POST /api/1/certificates/upload / PUT /api/1/certificates/ / POST /certificates.
Severity: High (CVSS 8.1/10). Data can be tampered with by attackers.
Update to 1.9.3.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual POST /api/1/certificates requests with malformed payloads or SQL meta-characters. Run grep -r 'lemur' . 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
-
1Identify exposure identify
grep -r 'lemur' . | 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
lemurを grep し、稼働しているサービス・バージョンを把握する。 -
2Hunt for indicators of compromise detect
grep 'POST /api/1/certificates' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'アクセスログで
POST /api/1/certificates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。 -
3Apply patch patch
Upgrade lemur to 1.9.3ステージング環境で 1.9.3 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 2 で見つけた異常検知の続報チェックを含めること。
-
4Post-deployment verification verify
Replay attack against POST /api/1/certificates 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
References
- advisory github.com
- advisory nvd.nist.gov
- package github.com
- package pypi.org
- web github.com
- web github.com
- web github.com