IBM Langflow OSS CVE-2026-104324

Requires an authenticated session on the Langflow OSS instance: the CVSS vector specifies PR:L, so the attacker must hold at least low-privilege valid credentials (self-registered, multi-tenant, or compromised account) and network reachability to the application - not fully anonymous/unauthenticated access. The flaw is a deserialization of untrusted data (CWE-502); the specific component, endpoint, or input field that performs the unsafe deserialization is not described in the available sources. No user interaction is required (UI:N) and attack complexity is low (AC:L). Primary limiting factors: valid authentication is mandatory, and exposure is concentrated in instances reachable by untrusted users or published on a network; affected deployments are IBM Langflow OSS 1.0.0 through 1.12.3 only.

This is a credible, promptly-actionable issue but not a drop-everything emergency. The CVSS 3.1 vector (AV:N/AC:L/PR:L/UI:N, C:H/I:H/A:H, score 8.8) describes network-reachable, low-complexity, authenticated code execution with full confidentiality, integrity and availability impact - consistent with a CWE-502 untrusted-data deserialization leading to RCE. The signals are not conflicting but several are simply absent: no EPSS probability was supplied, there is no CISA KEV listing, and no PoC or exploit reference is present, so there is no evidence of active exploitation or of published exploit code at the time of analysis. No SSVC fields (automatable, technical impact, exploitation) were provided; the only prioritization signal is the vuln.today Decision label 'this_week', which aligns with a high-severity authenticated RCE that is not yet known to be exploited. The key mitigating factor is PR:L - the attacker must already hold at least low-privilege authenticated access to the Langflow instance, which narrows the exploit population to instances exposed to untrusted or multi-tenant users (or reachable after credential compromise). Net: treat as a high-severity patch-this-week item; the absence of EPSS/KEV/PoC data means exploitation likelihood cannot be quantified and should not be assumed to be either high or negligible.

An attacker who holds valid low-privilege credentials to an IBM Langflow OSS instance (versions 1.0.0-1.12.3) submits crafted serialized data to a component that deserializes it without validation, causing arbitrary code execution on the server with the privileges of the Langflow process. Because the CVSS vector is network-facing with low attack complexity and no user interaction, any authenticated user - including a low-trust or compromised account - could trigger it against a default-reachable instance. No public exploit code or PoC reference was provided in the available data.