Opensearch: Protection Mechanism Failure
CVE-2026-18428 is a high-severity protection mechanism failure vulnerability in Opensearch from AWS, with a CVSS 3.1 base score of 8.8 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: 2.13 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 1% chance of exploitation within 30 days, higher than 63% of scored 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 | 2.13 through 3.5 | Not stated |
| GitHub | Opensearch | 2.13 through 3.6 | 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
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by CNA.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 4.0 | 8.7 | High | CNA |
| CVSS 3.1 | 8.8 | High | CNA |
Official description
A SQL query validation bypass in the Flint extension query handler in the OpenSearch SQL plugin allows a remote authenticated actor with async query access to execute arbitrary code on Apache Spark workers by sending a crafted SQL query to the direct query endpoint.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Protection Mechanism Failure
The product does not use or incorrectly uses a protection mechanism that provides sufficient defense against directed attacks against the product.
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 references
- docs.aws.amazon.com/opensearch-service/latest/developerguide/service-software.html
- opensearch.org/artifacts/by-version/?_gl=1*d14pqp*_up*MQ..*_ga*Nzc5NTAxNzM2LjE3ODM1NTA2NDA.*_ga_BQV14XK08F*cz…
- opensearch.org/artifacts/by-version/?_gl=1*d14pqp*_up*MQ..*_ga*Nzc5NTAxNzM2LjE3ODM1NTA2NDA.*_ga_BQV14XK08F*cz…
Other vulnerabilities in Opensearch
- 8.1 High severity
- 8.1 High severity
Recent Protection Mechanism Failure vulnerabilities
- 7.7 High severity
- 7.6 High severity
- 7.8 High severity
- 7.3 High severity
- 10.0 Critical severity
- 8.8 High severity
Spotted an error? Tell us.