Path Traversal in langflow (CVE-2026-42867)
Summary
Path traversal in langflow (CVE-2026-42867). Risk of unauthorized operations or information disclosure. Exploitable via POST /api/v1/knowledge_bases. Mitigation: upgrade to 1.9.0 or later.
Original description
The description as published by the source.
Langflow is a tool for building and deploying AI-powered agents and workflows. Prior to 1.9.0, Langflow is vulnerable to Path Traversal in the Knowledge Bases API (POST /api/v1/knowledge_bases). This occurs because user-supplied knowledge base names are used directly to create file paths without proper sanitization or containment checks. An authenticated attacker can exploit this flaw to create directories and write files anywhere on the server's filesystem. This vulnerability is fixed in 1.9.0.
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-2026-42867 has been found in langflow.
Attackers can target a specific entry point like POST /api/v1/knowledge_bases over the network to misuse the product.
Risk of unauthorized operations or information disclosure. CVSS score: 6.5/10.
What to do: upgrade langflow to 1.9.0 or later.
If unsure, ask your IT team or search "langflow CVE-2026-42867" on the vendor's site.
CVE-2026-42867 (langflow) — CWE-22 / CVSS v3 6.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: POST /api/v1/knowledge_bases / create_knowledge_base / name
Patched: 1.9.0 — 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.
Path traversal (CWE-22) exists in langflow. Attackers reach the vulnerable code path via POST /api/v1/knowledge_bases without authentication.
Check the vendor advisory for the affected versions of langflow. Attack surface: POST /api/v1/knowledge_bases / create_knowledge_base / name.
Severity: Medium (CVSS 6.5/10). Risk of unauthorized operations or information disclosure.
Update to 1.9.0.
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/v1/knowledge_bases requests with malformed payloads or SQL meta-characters. Run grep -r 'langflow' . 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 'langflow' . | 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
langflow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/v1/knowledge_bases' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'アクセスログで
POST /api/v1/knowledge_bases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 langflow to 1.9.0ステージング環境で 1.9.0 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/v1/knowledge_bases 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 github.com
- advisory nvd.nist.gov
- advisory github.com
- package github.com
- patch github.com
- web github.com
- web pypi.org