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Langflow CVE-2026-12944: How a Scanner Blocklist Gap Turns Into Root Code Execution

#security #vulnerability #langflow #ssrf

Langflow CVE-2026-12944: How a Scanner Blocklist Gap Turns Into Root Code Execution

Vulnerability overview

CVE-2026-12944 is a server-side request forgery and code execution flaw in IBM Langflow OSS, a visual framework for building LLM applications. IBM X-Force rates it 9.6 (Critical) on the CVSS v3 scale. The root cause is an incomplete blocklist in the component validation scanner: the scanner rejects dangerous modules such as subprocess, but leaves the socket and urllib standard libraries available. An authenticated user can therefore submit a component whose module-level code opens a network connection or fetches a URL, and that code runs on the server during validation.

A second flaw, CVE-2026-17628 (CVSS 5.4), is an authentication defect in the password reset endpoint. The user management API accepts a new password without verifying the current one. The two issues are tracked in the same advisory but have different mechanisms and different fixes.

Mechanism and exploitation conditions

The validation stage is the weak point. When a user submits a custom component, Langflow imports and evaluates it to confirm it is well formed. The scanner is supposed to strip or reject modules that can touch the operating system. It blocks subprocess but not socket or urllib, so a component that calls socket.connect() or urllib.request.urlopen() at module level passes the check and executes. The advisory describes exactly this path: authenticated users submit components containing those calls, and the server runs them during component validation.

The execution context raises the severity. The injected code runs with root privileges inside the Langflow container, according to the advisory. From there an attacker can open a reverse shell or read local files. Because Langflow commonly holds cloud credentials for the models and services it orchestrates, the same code path can reach AWS IAM role permissions and internal data stores such as PostgreSQL and Redis.

Two conditions bound real-world exploitation. The attacker needs a valid account on the Langflow instance, and the instance must expose the component submission feature. Self-hosted deployments that are reachable from untrusted networks and permit user registration meet both conditions.

CVE-2026-17628 is simpler to reach but lower impact. It requires an already-hijacked session. With that session, an attacker can set a new password without knowing the old one and lock the legitimate user out.

Impact

Successful exploitation of CVE-2026-12944 gives an attacker code execution on a host that sits inside the AI development pipeline. The immediate effects are file disclosure and reverse shell access. The larger effect is credential theft: Langflow stores or references the API keys and cloud roles its flows use, so root access to the container is a path to the wider environment. Lateral movement to internal databases follows the same credentials.

The password reset flaw adds a persistence and denial-of-service dimension. An attacker who already holds a session can convert it into durable account control and remove the original user.

No in-the-wild exploitation had been observed for either flaw at the time the advisory was published.

Affected products and versions

Langflow OSS is affected across a wide version range. CVE-2026-12944 affects versions 1.0.0 through 1.10.0. CVE-2026-17628 affects versions 1.0.0 through 1.10.2. The fix for both is version 1.10.3.

Because the affected range starts at 1.0.0, any self-hosted instance that has not been updated to 1.10.3 should be treated as vulnerable. Managed or hosted deployments depend on the provider's patch cadence.

Exposure context

A ZoomEye query for the product fingerprint shows a large internet-facing population. The query app="Langflow" returned 18,414 matching assets at the time of checking.

That number describes assets that match the Langflow fingerprint. It does not confirm that any of them are unpatched, reachable for component submission, or exploitable. Read it as an exposure indicator, not a count of vulnerable instances. A CVE-scoped query, vul.cve="CVE-2026-12944", returned 0, which means ZoomEye has not indexed this CVE identifier against assets; it does not mean no vulnerable instance is exposed.

Remediation and mitigations

Upgrade to Langflow OSS 1.10.3 or later. That release resolves both the scanner blocklist gap and the password reset defect.

Where an immediate upgrade is not possible, reduce the attack surface. Restrict network access to the Langflow interface so that only trusted users can reach it. Disable open registration if the deployment does not need it, since the flaw requires an authenticated user. Review which credentials the instance can reach and rotate any that were exposed while the instance was vulnerable.

After upgrading, confirm the running version, verify that the component submission path is not reachable from untrusted networks, and review authentication logs for sessions the organization cannot account for.

References

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