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CVE-2026-33873
Code Injection in langflow (CVE-2026-33873)
Summary
code injection in langflow (CVE-2026-33873). Successful exploitation can lead to full system takeover. Exploitable via ``input_value``. Mitigation: upgrade to `1.9.0` or later.
AI summary snake-internal / snake-material-v2
A vulnerability tracked as **CVE-2026-33873** has been found in langflow.
Attackers can target a specific entry point like ``input_value`` over the network to misuse the product.
Successful exploitation can lead to full system takeover. CVSS score: ?/10.
What to do: upgrade langflow to **1.9.0** or later.
If unsure, ask your IT team or search "langflow CVE-2026-33873" on the vendor's site.
CVE-2026-33873 (langflow) — CWE-94 /
Attack vector: remote (network-reachable) / no user interaction
Attack surface: `input_value` / `flow_id` / `provider` / `model_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.
❓ What is the problem
**arbitrary code execution** (CWE-94) exists in langflow. Attackers reach the vulnerable code path via ``input_value`` without authentication.
📍 Affected scope
langflow — . Attack surface: `input_value` / `flow_id` / `provider` / `model_name`.
🔥 Severity
Severity: ?. Successful exploitation can lead to full system takeover
🔧 How to fix
Update to **1.9.0**.
🛡️ 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 'langflow' .` 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
-
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。
-
6Apply 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 3 で見つけた異常検知の続報チェックを含めること。
-
7Post-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 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
PyPI
langflow
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.9.0"}]}]
pip
langflow
[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"1.9.0"}]}]
References
- advisory https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/33xxx/CVE-2026-33873.json
- advisory https://nvd.nist.gov/vuln/detail/CVE-2026-33873
- package https://github.com/langflow-ai/langflow
- web https://github.com/langflow-ai/langflow/blob/f7f4d1e70ba5eecd18162ec96f3571c2cfbcd1fc/src/backend/base/langflow/agentic/api/router.py#L252-L297
- web https://github.com/langflow-ai/langflow/blob/f7f4d1e70ba5eecd18162ec96f3571c2cfbcd1fc/src/backend/base/langflow/agentic/api/schemas.py#L20-L31
- web https://github.com/langflow-ai/langflow/blob/f7f4d1e70ba5eecd18162ec96f3571c2cfbcd1fc/src/backend/base/langflow/agentic/helpers/code_extraction.py#L11-L53
- web https://github.com/langflow-ai/langflow/blob/f7f4d1e70ba5eecd18162ec96f3571c2cfbcd1fc/src/backend/base/langflow/agentic/helpers/validation.py#L27-L47
- web https://github.com/langflow-ai/langflow/blob/f7f4d1e70ba5eecd18162ec96f3571c2cfbcd1fc/src/backend/base/langflow/agentic/services/assistant_service.py#L142-L156
- web https://github.com/langflow-ai/langflow/blob/f7f4d1e70ba5eecd18162ec96f3571c2cfbcd1fc/src/backend/base/langflow/agentic/services/assistant_service.py#L259-L300
- web https://github.com/langflow-ai/langflow/blob/f7f4d1e70ba5eecd18162ec96f3571c2cfbcd1fc/src/backend/base/langflow/agentic/services/assistant_service.py#L58-L79
- web https://github.com/langflow-ai/langflow/blob/f7f4d1e70ba5eecd18162ec96f3571c2cfbcd1fc/src/backend/base/langflow/api/utils/core.py#L38
- web https://github.com/langflow-ai/langflow/blob/f7f4d1e70ba5eecd18162ec96f3571c2cfbcd1fc/src/backend/base/langflow/api/v1/login.py#L96-L135
- web https://github.com/langflow-ai/langflow/blob/f7f4d1e70ba5eecd18162ec96f3571c2cfbcd1fc/src/backend/base/langflow/services/auth/utils.py#L156-L163
- web https://github.com/langflow-ai/langflow/blob/f7f4d1e70ba5eecd18162ec96f3571c2cfbcd1fc/src/backend/base/langflow/services/auth/utils.py#L39-L53
- web https://github.com/langflow-ai/langflow/blob/f7f4d1e70ba5eecd18162ec96f3571c2cfbcd1fc/src/lfx/src/lfx/custom/validate.py#L241-L272
- web https://github.com/langflow-ai/langflow/blob/f7f4d1e70ba5eecd18162ec96f3571c2cfbcd1fc/src/lfx/src/lfx/custom/validate.py#L394-L399
- web https://github.com/langflow-ai/langflow/blob/f7f4d1e70ba5eecd18162ec96f3571c2cfbcd1fc/src/lfx/src/lfx/custom/validate.py#L441-L443
- web https://github.com/langflow-ai/langflow/blob/f7f4d1e70ba5eecd18162ec96f3571c2cfbcd1fc/src/lfx/src/lfx/services/settings/auth.py#L71-L87
- web https://github.com/langflow-ai/langflow/security/advisories/GHSA-v8hw-mh8c-jxfc
- web https://github.com/pypa/advisory-database/tree/main/vulns/langflow/PYSEC-2026-82.yaml
- web https://github.com/advisories/GHSA-v8hw-mh8c-jxfc