IBM Langflow OSS CVE-2026-78569

Exploitation requires a valid authenticated session with at least low-privilege access to the IBM Langflow OSS instance (PR:L per CVSS). The attacker must be able to submit input to a flow component or API endpoint that passes through the security scanner - meaning the Langflow server's code-execution or evaluation features must be reachable by the attacker's account. Non-default configurations that restrict authenticated users from interacting with executable components would limit exposure. What limits exploitation: the mandatory authentication step (PR:L) prevents unauthenticated attacks; deployments where all authenticated users are fully trusted (e.g., internal single-tenant tools) face near-zero incremental risk; containerized deployments with restrictive seccomp/AppArmor profiles limit post-exploitation OS command reach.

The CVSS 3.1 score of 8.8 (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H) accurately reflects the severity for affected deployments: network-reachable, low complexity, no user interaction, full CIA impact, but gated on authenticated low-privilege access. This PR:L requirement is the primary real-world risk moderator. In enterprise Langflow deployments where all users are trusted (single-tenant internal tool), this vulnerability has limited incremental risk. However, in multi-tenant SaaS-style deployments or shared team instances where low-privilege accounts are issued to less-trusted users, the risk is elevated because any authenticated user becomes a potential attacker. EPSS data is not provided, and CISA KEV status is negative (no confirmed active exploitation). No public POC is identified. The denylist-bypass class of vulnerability is well-understood by attackers familiar with sandbox escape techniques, so the practical exploitation complexity is lower than AC:L might suggest to a novice - a skilled attacker with an account can iterate quickly on bypass payloads. Priority should be high for public-facing or multi-tenant Langflow instances, moderate for single-tenant internal deployments.

An attacker with a low-privilege Langflow account - obtained via credential reuse, phishing, or a shared/demo account - crafts a flow component input or API parameter containing an OS command injection payload designed to circumvent the security scanner's denylist. The scanner passes the crafted payload because the specific syntax used is not on the blocklist, and the underlying execution engine evaluates it, running arbitrary OS commands as the process account of the Langflow server. No public POC is known, but the attack is straightforward for anyone familiar with denylist evasion techniques (alternate encodings, shell metacharacters, indirect invocation).