Affects widely used IBM WebSphere Liberty; privilege escalation can grant admin control across enterprise app servers and disrupt services.
CVE-2026-18499
Privilege escalation in IBM WebSphere Liberty collectives (v17.0.0.3–26.0.0.8).
Is CVE-2026-18499 being exploited?
Not confirmed. CVE-2026-18499 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 0.27% probability of exploitation in the next 30 days.
How severe is CVE-2026-18499?
CVE-2026-18499 is rated High with a CVSS score of 8.1. 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-2026-18499?
Yes. A fix has been recorded for CVE-2026-18499. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-18499 affect?
CVE-2026-18499 affects IBM WebSphere Application Server - Liberty 17.0.0.3, IBM WebSphere Application Server - Liberty up to 26.0.0.8, Liberty collectives / Liberty servers. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-18499?
Restrict access to Liberty collectives, increase logging/monitoring, and apply vendor patch when released.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
An attacker with access to a Liberty collective can escalate to administrative/root on Liberty servers, enabling data access, lateral movement, and service disruption.
Immediate action required
- affected>= 17.0.0.3 and <= 26.0.0.8
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.