Auth bypass in IBM i (widely deployed enterprise OS) enables unauthorized access to core systems and data; impactful across many organizations.
CVE-2026-18221
Authentication bypass in IBM i 7.3–7.6 allowing remote unauthorized access
Is CVE-2026-18221 being exploited?
Not confirmed. CVE-2026-18221 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 0.33% probability of exploitation in the next 30 days.
How severe is CVE-2026-18221?
CVE-2026-18221 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-2026-18221?
Yes. A fix has been recorded for CVE-2026-18221. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-18221 affect?
CVE-2026-18221 affects IBM i 7.6, IBM i 7.5, IBM i 7.4, IBM i 7.3. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-18221?
Apply IBM security updates immediately and restrict network access to IBM i services.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
Remote authentication bypass permitting attackers to access IBM i accounts, read/modify data, execute commands, and pivot within networks.
Immediate action required
- affected7.6
- affected7.5
- affected7.4
- affected7.3
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.