CVE-2026-18221
HIGH 8.1IBM i 7.6, 7.5, 7.4, and 7.3 could allow a remote attacker to gain unauthorized access due to improper validation of client-supplied authentication parameters.
ELEVATED IMPACT
Severe if exploited (CVSS 8.1), but no known exploitation and low modeled probability. Patch on a normal cadence.
Exploitation likelihood
—EPSS not yet scored
○ In CISA KEV
○ Public exploit / PoC
Impact if exploited
8.1CVSS 3.1 · HIGH
- ConfidentialityHigh
- IntegrityHigh
- AvailabilityHigh
What an attacker needs
- ✓Access: Reachable over the network — no local access needed
- ✓Privileges: No account or privileges required
- ✓User interaction: No user interaction needed
- ⚠Complexity: Needs a race window or specific setup
✓ lowers the bar for an attacker · ⚠ raises it
Proof of concept & exploit code
- github-search Search GitHub for public PoC repos
Test against your own equipment
curl -s https://vulnpedia.com/cve/CVE-2026-18221/poc.jsonMachine-readable PoC index for this CVE (for automation).Listed for defensive triage, patch verification, and authorized testing on systems you own. Machine-readable: /cve/CVE-2026-18221/poc.json
Weakness (CWE)
- CWE-287: Improper Authentication
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
All CVSS metrics
- HIGH 8.1 v3.1 · CNA Primary
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H - HIGH 8.1 v3.1 · NVD Primary
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H