Langflow OSS: Improper Authentication
CVE-2026-18891 is a high-severity improper authentication vulnerability in Langflow OSS from IBM, with a CVSS 3.1 base score of 8.2 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected Langflow OSS versions: 1.0.0 through 1.11.1. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.54% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Langflow to 1.11.2 or a later version.
- Read the advisory on ibm.com for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| IBM | Langflow OSS | 1.0.0 through 1.11.1 | Not stated |
| Langflow | Langflow | 1.0.0 up to, but not including, 1.11.2 | 1.11.2 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- LowLimited modification of data is possible.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:L/A:N. Scored by CNA (us.ibm.com).
Official description
IBM Langflow OSS 1.0.0 through 1.11.1 could allow a remote attacker to execute arbitrary flows and access sensitive information due to improper authentication.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Authentication
When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct.
How developers prevent this class of flaw
- Use an authentication framework or library such as the OWASP ESAPI Authentication feature.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Other vulnerabilities in Langflow OSS
- 8.1 High severity
- 9.8 Critical severity
- 8.8 High severity
- 8.8 High severity
- 8.8 High severity
- 8.8 High severity
Recent Improper Authentication vulnerabilities
- 7.5 High severity
- 9.8 Critical severity
- 7.4 High severity
- 7.3 High severity
- 8.8 High severity
- 8.1 High severity
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