CVE-2026-7657 Overview
CVE-2026-7657 is a Server-Side Request Forgery (SSRF) vulnerability [CWE-918] affecting IBM Langflow OSS versions 1.0.0 through 1.10.3. The flaw stems from incomplete and ineffective SSRF protection enforcement within the Langflow platform. An authenticated attacker with low privileges can exploit this weakness over the network to coerce the server into issuing arbitrary outbound requests. Successful exploitation can expose confidential data reachable from the Langflow host, including internal services and cloud metadata endpoints. IBM published a security advisory documenting the affected releases and remediation guidance.
Critical Impact
Authenticated attackers can abuse Langflow to reach internal network resources and exfiltrate sensitive data through server-initiated requests.
Affected Products
- IBM Langflow OSS 1.0.0 through 1.10.3
- Deployments using bundled Langflow SSRF protection controls
- Environments exposing Langflow to authenticated but untrusted users
Discovery Timeline
- 2026-08-05 - CVE-2026-7657 published to NVD
- 2026-08-05 - Last updated in NVD database
Technical Details for CVE-2026-7657
Vulnerability Analysis
Langflow is an open-source framework for building LLM-powered applications and flows. The product includes components that fetch remote resources over HTTP as part of flow execution. IBM implemented SSRF protection to restrict outbound targets, but the enforcement is incomplete. Attackers with valid low-privilege credentials can craft requests that bypass the filters. Once bypassed, the server issues requests to arbitrary destinations chosen by the attacker.
Because the request originates from the Langflow host, attackers can reach services that trust the server's network position. Common SSRF targets include cloud provider instance metadata services, internal admin interfaces, and databases bound to loopback or private ranges. The vulnerability impacts confidentiality but does not directly affect integrity or availability of the Langflow instance itself.
Root Cause
The root cause is incomplete validation of user-supplied URLs and hosts within Langflow components that perform outbound HTTP fetches. Filter logic fails to normalize or reject inputs that resolve to restricted address ranges. Techniques such as DNS rebinding, alternate IP encodings, redirect chains, or protocol handler abuse can defeat the checks. The result is an SSRF primitive controlled by any authenticated user of the platform.
Attack Vector
The attack vector is network-based and requires low privileges with no user interaction. An authenticated attacker submits a flow or component configuration that instructs Langflow to fetch a URL pointing at an internal resource. The Langflow server performs the request and returns response content or side-channel signals to the attacker. Refer to the IBM Security Advisory for vendor-supplied technical detail.
Detection Methods for CVE-2026-7657
Indicators of Compromise
- Outbound HTTP requests from the Langflow server to internal IP ranges such as 10.0.0.0/8, 172.16.0.0/12, and 192.168.0.0/16
- Connections from Langflow to cloud metadata endpoints such as 169.254.169.254
- Unexpected DNS lookups from the Langflow host targeting internal hostnames
- Langflow application logs showing URL fetch operations initiated by low-privilege user accounts
Detection Strategies
- Baseline normal outbound destinations for Langflow and alert on deviations to private or link-local ranges
- Correlate Langflow authentication events with subsequent egress traffic to identify user-driven SSRF attempts
- Inspect flow definitions and component configurations for URLs referencing internal or metadata addresses
Monitoring Recommendations
- Forward Langflow application and reverse proxy logs to a centralized SIEM for URL-fetch analytics
- Enable network flow logging on the subnet hosting Langflow and alert on egress to non-approved destinations
- Monitor cloud audit logs for use of instance credentials that would only be reachable via metadata service abuse
How to Mitigate CVE-2026-7657
Immediate Actions Required
- Upgrade IBM Langflow OSS to a fixed release as directed in the IBM Security Advisory
- Restrict Langflow access to trusted authenticated users and enforce least privilege on accounts that can define flows
- Place Langflow behind an egress proxy that denies traffic to private, loopback, and metadata address ranges
Patch Information
IBM has published remediation guidance for CVE-2026-7657 in the vendor advisory. Consult the IBM Security Advisory for fixed version details and upgrade procedures for Langflow OSS 1.0.0 through 1.10.3.
Workarounds
- Enforce a strict egress allowlist at the network layer so Langflow can only reach approved external endpoints
- Block access from the Langflow host to cloud instance metadata services using IMDSv2 enforcement or host firewall rules
- Disable or gate Langflow components that perform arbitrary URL fetches until the patch is applied
# Example iptables rules to block SSRF-relevant destinations from the Langflow host
iptables -A OUTPUT -d 169.254.169.254 -j REJECT
iptables -A OUTPUT -d 127.0.0.0/8 -j REJECT
iptables -A OUTPUT -d 10.0.0.0/8 -j REJECT
iptables -A OUTPUT -d 172.16.0.0/12 -j REJECT
iptables -A OUTPUT -d 192.168.0.0/16 -j REJECT
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
