OpenSearch: Undefined Behavior for Input to API
CVE-2026-19311 is a high-severity undefined behavior for input to API vulnerability in OpenSearch from AWS, with a CVSS 3.1 base score of 8.1 out of 10. It can be exploited remotely over the network by an attacker with a low-privileged account, without any action from a user. Affected OpenSearch versions: 2.4 through 3.5. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.58% 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
- Check which version of OpenSearch you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on aws.amazon.com for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| AWS | OpenSearch | 2.4 through 3.5 | Not stated |
| GitHub | OpenSearch | 2.4.0 through 2.19.5; 3.0.0 through 3.7.0 | Not stated |
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
- LowA basic user account is enough.
- 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
- HighData or code can be modified at will.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N. Scored by CNA.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 8.6 | High | CNA |
| CVSS 3.1 | 8.1 | High | CNA |
Official description
Missing authorization in the Execute Monitor API in Amazon OpenSearch Alerting plugin might allow an authenticated remote user to read, modify, or delete arbitrary index data via a crafted inline monitor request with unintentional data source and input index parameters.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Undefined Behavior for Input to API
The behavior of this function is undefined unless its control parameter is set to a specific value.
More Undefined Behavior for Input to API vulnerabilities (CWE-475)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Other vulnerabilities in OpenSearch
- 8.8 High severity
- 8.1 High severity
Recent Undefined Behavior for Input to API vulnerabilities
- 7.5 High severity
- 9.8 Critical severity
- 7.5 High severity
- 7.5 High severity
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