AI Threat AlertCVE-2026-110843: n8n: unauthenticated OAuth endpoint exhausts disk
HIGHCVE-2026-110843 is an uncontrolled resource consumption flaw in n8n's unauthenticated OAuth authorize endpoint. It resolves clients by URL path but stores the caller's raw identifier as the record key, so identifiers that differ only in their query string each create a new client record and bypass the registration cap. An attacker needs no credentials. Repeated requests grow the database until the disk fills, which can take down the workflow automation platform and every AI agent workflow that runs on it. No CVSS score, EPSS data, KEV listing or public exploit is available yet, so the risk should be treated as unscored. The flaw is trivial to trigger and the vendor has published an advisory, so exploitation is plausible for any internet-exposed instance. Upgrade to n8n 2.41.4, or to 2.42.1 on the 2.42.x line. Until then, restrict or rate-limit access to the OAuth authorize endpoint at the reverse proxy and alert on database and disk growth.
What is the risk?
Medium to high for internet-exposed n8n instances, with availability as the main impact. Exploitation is unauthenticated, remote, low complexity and needs no user interaction. The weakness is CWE-770 (allocation of resources without limits). There is no confidentiality or integrity impact described. No CVSS, EPSS, KEV or public exploit data exists at publication, so this assessment rests on the advisory description. Self-hosted instances on small disks, or where the database shares a volume with other services, are most exposed.
How does the attack unfold?
What systems are affected?
| Package | Ecosystem | Vulnerable Range | Patched |
|---|---|---|---|
| n8n | npm | — | No patch |
Do you use n8n? You're affected.
How severe is it?
What should I do?
1 step1) Upgrade to n8n 2.41.4 or later, or to 2.42.1 or later on the 2.42.x line. 2) Until patched, block or rate-limit unauthenticated access to the OAuth authorize endpoint at the reverse proxy or WAF, and deny requests with unusually long or varied query strings. 3) Do not expose n8n directly to the internet; place it behind a VPN or an authenticating proxy. 4) Monitor disk usage and database growth, and alert on rapid increases. 5) Look for an abnormal count of OAuth client records and repeated authorize requests from a single source in access logs. 6) Put the n8n database on a dedicated volume with quotas, and clean up injected client records after patching.
What does CISA's SSVC say?
Source: CISA Vulnrichment (SSVC v2.0). Decision based on the CISA Coordinator decision tree.
How is it classified?
Which compliance frameworks are affected?
This CVE is relevant to:
Frequently Asked Questions
What is CVE-2026-110843?
CVE-2026-110843 is an uncontrolled resource consumption flaw in n8n's unauthenticated OAuth authorize endpoint. It resolves clients by URL path but stores the caller's raw identifier as the record key, so identifiers that differ only in their query string each create a new client record and bypass the registration cap. An attacker needs no credentials. Repeated requests grow the database until the disk fills, which can take down the workflow automation platform and every AI agent workflow that runs on it. No CVSS score, EPSS data, KEV listing or public exploit is available yet, so the risk should be treated as unscored. The flaw is trivial to trigger and the vendor has published an advisory, so exploitation is plausible for any internet-exposed instance. Upgrade to n8n 2.41.4, or to 2.42.1 on the 2.42.x line. Until then, restrict or rate-limit access to the OAuth authorize endpoint at the reverse proxy and alert on database and disk growth.
Is CVE-2026-110843 actively exploited?
No confirmed active exploitation of CVE-2026-110843 has been reported, but organizations should still patch proactively.
How to fix CVE-2026-110843?
1) Upgrade to n8n 2.41.4 or later, or to 2.42.1 or later on the 2.42.x line. 2) Until patched, block or rate-limit unauthenticated access to the OAuth authorize endpoint at the reverse proxy or WAF, and deny requests with unusually long or varied query strings. 3) Do not expose n8n directly to the internet; place it behind a VPN or an authenticating proxy. 4) Monitor disk usage and database growth, and alert on rapid increases. 5) Look for an abnormal count of OAuth client records and repeated authorize requests from a single source in access logs. 6) Put the n8n database on a dedicated volume with quotas, and clean up injected client records after patching.
What systems are affected by CVE-2026-110843?
This vulnerability affects the following AI/ML architecture patterns: agent frameworks, workflow automation platforms, LLM orchestration pipelines.
What is the CVSS score for CVE-2026-110843?
No CVSS score has been assigned yet.
What is the AI security impact?
Affected AI Architectures
MITRE ATLAS Techniques
AML.T0029Denial of AI ServiceAML.T0049Exploit Public-Facing ApplicationCompliance Controls Affected
What are the technical details?
Original Advisory
n8n before 2.41.4 and 2.42.x before 2.42.1 contains an uncontrolled resource consumption vulnerability in the unauthenticated OAuth authorize endpoint, which resolves clients by URL path but stores the caller's raw identifier as the record key. Unauthenticated attackers can send identifiers differing only in their query string to create unlimited first-party client records that bypass the registration cap, growing the database until the disk fills.
Exploitation Scenario
An attacker finds an internet-exposed n8n instance that runs AI agent workflows. They script a loop of unauthenticated requests to the OAuth authorize endpoint with the same client path but a different query string each time, such as ?x=1, ?x=2, and so on. Each request creates a new first-party client record and the registration cap never triggers. Over hours the database grows until the disk fills, n8n and its database crash, and all agent workflows and automations stop until the operator frees space and cleans up the records.
Weaknesses (CWE)
CWE-770Allocation of Resources Without Limits or ThrottlingPrimaryCWE-770Allocation of Resources Without Limits or ThrottlingCWE-770 — Allocation of Resources Without Limits or Throttling: The product allocates a reusable resource or group of resources on behalf of an actor without imposing any intended restrictions on the size or number of resources that can be allocated.
- [Requirements] Clearly specify the minimum and maximum expectations for capabilities, and dictate which behaviors are acceptable when resource allocation reaches limits.
- [Architecture and Design] Limit the amount of resources that are accessible to unprivileged users. Set per-user limits for resources. Allow the system administrator to define these limits. Be careful to avoid CWE-410.
Source: MITRE CWE corpus.
References
Timeline
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