{"id":"CVE-2026-90991","kind":"vulnerability","aliases":["CVE-2026-90991"],"related":[],"title":"Langflow: authenticated users can exhaust resources and cause denial of service","description":"IBM Langflow OSS 1.0.0 through 1.12.4 could allow a remote authenticated attacker to cause a denial of service due to allocation of resources without limits or throttling.","summary":"IBM Langflow OSS versions 1.0.0 through 1.12.4 allow a logged-in remote user to trigger unlimited resource allocation. An attacker can use this to make the service unavailable.","severity":"medium","cvss":6.5,"epss":null,"exploited":false,"exploited_at":null,"products":[{"name":"Langflow OSS","fixed":["1.12.5"],"affected":">= 1.0.0, <= 1.12.4","ecosystem":"vendor"}],"ecosystems":[],"tags":["ai-tooling","langflow","self-hosted"],"not_affected_if":["no-authenticated-user-exposure","version-outside-range"],"how_to_check":"- Check the installed Langflow version with `langflow --version` or the package manager, and compare it against the affected range `1.0.0` to `1.12.4`.\n- Confirm whether the Langflow instance is reachable from untrusted networks and whether accounts can be created or obtained by outsiders.","fix":"Upgrade Langflow OSS to 1.12.5 (IBM: back up the installation, follow the Prepare to upgrade steps, test flows).","status":"open","published_at":"2026-10-29T16:20:05+00:00","first_seen_at":"2026-10-29T16:26:03+00:00","triaged_at":"2026-10-29T16:31:17+00:00","updated_at":"2026-10-29T16:32:37+00:00","category":"ai-tooling","confidence":0.85,"triage":{"at":"2026-10-29T16:31:17Z","model":"claude-haiku-5-5","output":{"fix":"unknown","reach":"network","title":"Langflow: authenticated users can exhaust resources and cause denial of service","impact":"low","summary":"IBM Langflow OSS versions 1.0.0 through 1.12.4 allow a logged-in remote user to trigger unlimited resource allocation. An attacker can use this to make the service unavailable.","audience":"businesses","category":"ai-tooling","nicknames":[],"who_cares":["langflow","self-hosted","ai-tooling"],"confidence":0.6,"fix_status":"unknown","needs_auth":"yes","worst_case":"Service becomes unavailable through resource exhaustion by an authenticated user.","analyst_note":"Find the IBM security bulletin for CVE-2026-90991 to confirm the fixed version and affected endpoint; sources cite only NVD.","how_to_check":"- Check the installed Langflow version with `langflow --version` or the package manager, and compare it against the affected range `1.0.0` to `1.12.4`.\n- Confirm whether the Langflow instance is reachable from untrusted networks and whether accounts can be created or obtained by outsiders.","plain_action":"","needs_analyst":true,"not_affected_if":["version-outside-range","no-authenticated-user-exposure"],"who_is_affected":"Teams running self-hosted IBM Langflow OSS in the affected version range where remote users hold valid accounts. The sources do not describe the specific endpoint or configuration needed, so unknown. Instances that are not network-reachable by untrusted users, or that run versions outside the range, can skip it.","user_interaction":"no","needs_special_setup":"unknown","severity_if_unknown":"medium"},"cost_usd":0.000701,"input_tokens":4098,"output_tokens":583,"severity_before":"medium"},"analyst_status":"done","analyst_note":"Find the IBM security bulletin for CVE-2026-90991 to confirm the fixed version and affected endpoint; sources cite only NVD.","search":"'-2026':13A,16A '-90991':14A,17A '1.0.0':31B,59C '1.12.4':33B,61C 'ai':21B 'ai-tool':20B 'alloc':45B,76C 'allow':34B,63C 'attack':47B,67C 'authent':2A,66C 'caus':8A,69C 'could':62C 'cve':12A,15A 'denial':9A,71C 'due':74C 'exhaust':5A 'host':26B 'ibm':27B,56C 'langflow':1A,18A,23B,28B,57C 'limit':80C 'log':37B 'logged-in':36B 'make':52B 'oss':19A,29B,58C 'remot':39B,65C 'resourc':6A,44B,78C 'self':25B 'self-host':24B 'servic':11A,54B,73C 'throttl':82C 'tool':22B 'trigger':42B 'unavail':55B 'unlimit':43B 'use':49B 'user':3A,40B 'version':30B 'without':79C","nicknames":[],"mitigations":[],"who_affected":"Self-hosted Langflow OSS 1.0.0 through 1.12.4 where outsiders can hold or obtain a valid account; any logged-in user can exhaust server resources and make the service unavailable. IBM does not name the vulnerable endpoint. Instances on 1.12.5 or later, or reachable only by fully trusted users, can skip it.","tier":"B","verified":{"fix":{"at":"2026-10-29T16:32:37Z","by":"analyst","doc":"https://www.ibm.com/support/pages/security-bulletin-langflow-oss-affected-multiple-vulnerabilities-1","run_id":1055},"products":{"at":"2026-10-29T16:32:37Z","by":"analyst","doc":"https://www.ibm.com/support/pages/security-bulletin-langflow-oss-affected-multiple-vulnerabilities-1","run_id":1055},"who_affected":{"at":"2026-10-29T16:32:37Z","by":"analyst","doc":"https://www.ibm.com/support/pages/security-bulletin-langflow-oss-affected-multiple-vulnerabilities-1","run_id":1055}},"analyst_revisit_at":null,"fix_status":"available","audience":"businesses","plain_action":null,"first_public_at":"2026-10-29T16:20:05+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","cvss_by":"psirt@us.ibm.com","poc_count":0,"sources":[{"source":"nvd","external_id":"CVE-2026-90991","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-90991","severity":null,"published_at":"2026-10-29T16:20:05+00:00","modified_at":"2026-10-29T16:20:05+00:00","first_seen_at":"2026-10-29T16:26:03+00:00","fetched_at":"2026-10-29T16:26:03+00:00","note":null},{"source":"analyst","external_id":"CVE-2026-90991:1055","url":null,"severity":null,"published_at":"2026-10-29T16:32:37+00:00","modified_at":"2026-10-29T16:32:37+00:00","first_seen_at":"2026-10-29T16:32:37+00:00","fetched_at":"2026-10-29T16:32:37+00:00","note":"IBM bulletin (19 Oct 2026) lists CVE-2026-90991 (CWE-770, CVSS 6.5, auth required) affecting Langflow OSS 1.0.0-1.12.4, fixed in 1.12.5. Bulletin does not name the endpoint; no workaround for this CVE (MCP stdio controls are for other CVEs). No exploitation or PoC found."}],"documents":[{"id":17755,"url":"https://www.ibm.com/support/pages/security-bulletin-langflow-oss-affected-multiple-vulnerabilities-1","title":"IBM Security Bulletin: Langflow OSS is affected by multiple vulnerabilities (1.12.5)","kind":"advisory","source":"analyst","publisher":null,"text":null,"published_at":null,"relation":"advisory","confidence":null,"note":null}],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}