Vulnerability in langflow (CVE-2026-105741)
Summary
Vulnerability in langflow (CVE-2026-105741). Data can be tampered with by attackers. Exploitable via POST /api/v1/mcp/project/{project_id}/install. Mitigation: upgrade to 1.10.3 or later.
Original description
The description as published by the source.
Description:
Summary
An IP spoofing vulnerability in the Model Context Protocol (MCP) configuration installation endpoint (POST /api/v1/mcp/project/{project_id}/install) allowed authenticated remote attackers to bypass the "local-only" access restriction. By sending a spoofed X-Forwarded-For: 127.0.0.1 header, an attacker could make the server treat the request as originating from localhost, letting them write/overwrite an MCP client configuration file on the server's filesystem.
Details
The vulnerability lived in the get_client_ip helper, used to enforce the local-only gate for install_mcp_config. It trusted the leftmost (fully client-controlled) entry of X-Forwarded-For unconditionally, with no check for whether the request had actually passed through a trusted proxy.
Vulnerable code (introduced by commit d3d06be8e5, first released in v1.5.0): src/backend/base/langflow/api/v1/mcp_projects.py
def get_client_ip(request: Request) -> str:
# Check for X-Forwarded-For header (common when behind proxies)
forwarded_for = request.headers.get("X-Forwarded-For")
if forwarded_for:
# The client IP is the first one in the list
return forwarded_for.split(",")[0].strip()
if request.client:
return request.client.host
return "255.255.255.255"
@router.post("/{project_id}/install")
async def install_mcp_config(
project_id: UUID,
body: MCPInstallRequest, # {client: str, transport: "sse" | "str…
Source: NIST National Vulnerability Database 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-2026-105741 has been found in langflow.
Attackers can target a specific entry point like POST /api/v1/mcp/project/{project_id}/install over the network to misuse the product.
Data can be tampered with by attackers. CVSS score: 7.1/10.
What to do: upgrade langflow to 1.10.3 or later.
If unsure, ask your IT team or search "langflow CVE-2026-105741" on the vendor's site.
CVE-2026-105741 (langflow) — CWE-290 / CVSS v3 7.1
Attack vector: remote (network-reachable) / no user interaction
Attack surface: POST /api/v1/mcp/project/{project_id}/install / get_client_ip / install_mcp_config / d3d06be8e5
Patched: 1.10.3 — 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-290) exists in langflow. Attackers reach the vulnerable code path via POST /api/v1/mcp/project/{project_id}/install.
Check the vendor advisory for the affected versions of langflow. Attack surface: POST /api/v1/mcp/project/{project_id}/install / get_client_ip / install_mcp_config / d3d06be8e5.
Severity: High (CVSS 7.1/10). Data can be tampered with by attackers.
Update to 1.10.3.
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/v1/mcp/project/{project_id}/install 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/mcp/project/{project_id}/install' /var/log/nginx/access.log | grep -E '(unusual_payload|sqli_pattern)'アクセスログで
POST /api/v1/mcp/project/{project_id}/install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 1.10.3ステージング環境で 1.10.3 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/v1/mcp/project/{project_id}/install 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 nvd.nist.gov
- advisory github.com
- package github.com
- package pypi.org
- web github.com
- web github.com
- web github.com
- web github.com
- web github.com