CVE-2026-33760 is a high-severity security vulnerability in langflow (pip), affecting versions < 1.9.0. It is fixed in 1.9.0.
Summary Langflow's /api/v1/monitor router exposes 7 endpoints that perform read, write, and delete operations on user-owned resources, messages, sessions, build artifacts, and LLM transaction logs, without verifying that the authenticated requester owns the targeted resource. Any authenticated user can read, modify, rename, or permanently delete another user's data by supplying the target's resource ID or flowid. This is a classic IDOR/BOLA vulnerability. Notably, the same source file (monitor.py) contains one correctly-implemented endpoint that uses an ownership check, demonstrating the correct pattern was known but inconsistently applied. Details Source file: src/backend/base/langflow/api/v1/monitor.py The correct pattern (used only in GET /monitor/messages, lines 77–80): All 7 vulnerable endpoints are missing this guard: GET /api/v1/monitor/builds (lines 27–33), reads build data for any flowid: DELETE /api/v1/monitor/messages (lines 102–107), deletes any message by UUID: PUT /api/v1/monitor/messages/{messageid} (lines 110–134), overwrites any message: PATCH /api/v1/monitor/messages/session/{oldsessionid} (lines 137–171), renames any session: DELETE /api/v1/monitor/messages/session/{sessionid} (lines 174–188), bulk-deletes any session: GET /api/v1/monitor/transactions (lines 191–211), reads LLM prompt/response logs for any flowid: DELETE /api/v1/monitor/builds, deletes build records for any flowid: Shares the same root cause as endpoint #1 (GET /builds): flowid is accepted as a bare query parameter and passed to the deletion path without a WHERE Flow.userid == currentuser.id ownership check, so any authenticated user can destroy another user's build artifacts. PoC Tested on Langflow v1.7.3 (langflowai/langflow:1.7.3) with two accounts: langflow (victim) and attackertest (attacker). All 6 demonstrated attack vectors confirmed (the 7th, DELETE /builds, shares the GET /builds root cause and was not separately scripted). After attacker operations: victim's message text read "TAMPERED BY ATTACKER", session renamed to attacker-controlled name, second session completely deleted. Impact This vulnerability affects any Langflow deployment with multiple users (team instances, SaaS deployments, enterprise self-hosted). Confidentiality: GET /transactions exposes the full LLM conversation history, user-submitted prompts and model responses, for any flow by flow_id. In healthcare, legal, financial, or HR deployments this directly exposes sensitive and potentially regulated data (HIPAA, GDPR). GET /builds exposes internal workflow execution state. Integrity: PUT /messages/{id} allows rewriting any stored message, corrupting chat history, audit trails, and RAG-indexed memory. PATCH /messages/session/{id} allows renaming sessions, breaking session continuity and potentially injecting victim context into attacker-controlled namespaces. Availability: DELETE /messages and DELETE /messages/session/{id} enable permanent, irreversible destruction of another user's conversation history and LLM logs. No recovery mechanism exists once data is deleted. Any registered user account (including self-registered accounts if registration is open) has unrestricted cross-user access to all 6 operations against any other user's data.
CVE-2026-33760 has a CVSS score of 8.8 (High). The vector is network-reachable, low privileges required, and no user interaction. A CVSS score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether this affects your application depends on whether the vulnerable code is present and reachable in your environment.
A fixed version is available (1.9.0). Upgrading removes the vulnerable code path.
pip
langflow (< 1.9.0)langflow → 1.9.0 (pip)Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter instead of chasing every advisory.
Kodem's runtime-powered SCA identifies whether CVE-2026-33760 is reachable in your applications. Explore open-source security for your team.
See if CVE-2026-33760 is reachable in your applications. Get a demo
Upgrade langflow to 1.9.0 or later to resolve this vulnerability.
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
CVE-2026-33760 is a high-severity security vulnerability in langflow (pip), affecting versions < 1.9.0. It is fixed in 1.9.0.
CVE-2026-33760 has a CVSS score of 8.8 (High). This score reflects the worst-case severity of the vulnerability, not your specific exposure. Whether it represents real risk in your environment depends on whether the vulnerable code is present and reachable.
langflow (pip) versions < 1.9.0 is affected.
Yes. CVE-2026-33760 is fixed in 1.9.0. Upgrade to this version or later.
Whether CVE-2026-33760 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
Upgrade langflow to 1.9.0 or later.