CVE-2026-18428
Auth SQL validation bypass enabling RCE on Spark workers via OpenSearch Flint plugin
Is CVE-2026-18428 being exploited?
Not confirmed. CVE-2026-18428 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.69% probability of exploitation in the next 30 days.
How severe is CVE-2026-18428?
CVE-2026-18428 is rated High with a CVSS score of 8.7. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-18428?
Yes. A fix has been recorded for CVE-2026-18428. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-18428 affect?
CVE-2026-18428 affects OpenSearch SQL plugin (Flint extension), OpenSearch direct query endpoint, Apache Spark worker nodes. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-18428?
Disable Flint direct query or restrict async query access; apply vendor patch when released.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Authenticated attacker with async query access can execute arbitrary code on Apache Spark worker nodes via a crafted SQL to the Flint direct query endpoint.
Immediate action required
- affected>= 2.13 and <= 3.5
- affected>= 2.13 and <= 3.6
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.