CVE-2026-17075 is a medium severity (CVSS 6.5) improper authentication flaw in IBM i 7.3, 7.4, 7.5 and 7.6, in how authentication tokens are validated. A remote attacker could obtain sensitive information and perform unauthorized operations. IBM provides PTFs under 5770-SS1 Option 34.
What's affected
IBM i 7.6, 7.5, 7.4 and 7.3, per IBM's bulletin and the NVD record. IBM lists these PTFs for 5770-SS1 Option 34:
- IBM i 7.6: SJ10907
- IBM i 7.5: SJ10906
- IBM i 7.4: SJ10905
- IBM i 7.3: SJ10904
IBM says to address the issue now and recommends that users of unsupported IBM i releases move to a supported, fixed version.
How to check if you're exposed
IBM i 7.3 through 7.6 are all in scope, so every supported and recently supported release needs a look. On each partition, confirm the installed release and then check whether the PTF for your release is loaded. From a command line:
DSPPTF LICPGM(5770SS1)
Look for the PTF number listed for your release in the table above, with a status of Applied or Permanently applied. You can also use option 10 of GO LICPGM to confirm the release. Do this on every LPAR, including test and recovery systems, because they are often patched last.
What to do now
- List every IBM i partition and its release, including test and disaster recovery systems.
- Find the PTF for your release in the table above, and order it from IBM Fix Central or through your usual PTF process.
- Apply the PTF and restart as the PTF cover letter requires.
- Check the PTF status with DSPPTF and record it.
- Limit access to IBM i network services to the hosts and users that need them.
Why it matters
CWE-287 is improper authentication. The system does not fully verify a token before trusting it. No privileges or user interaction are needed, but attack complexity is high, which keeps the score at 6.5 with high confidentiality and low integrity impact.
High complexity suggests specific conditions must line up. Even so, an unauthenticated network flaw in an administrative web component is the kind that scanners probe. It shares a bulletin with CVE-2026-17069, rated 8.1, so one PTF set serves both.
The weakness class here is CWE-287 (Improper Authentication). The NVD record scores it 6.5, which is medium severity. IBM's bulletin gives the same score. The CVSS vector reads attack vector over the network, high attack complexity, no privileges required, no user interaction. Scope is unchanged. Impact on confidentiality, integrity and availability is rated high, low and none. The record's KEV flag is false, so this CVE is not in CISA's Known Exploited Vulnerabilities catalog, and the advisory I fetched does not report exploitation.
Safeguard's Gold directory tracks this CVE, and reachability analysis helps you decide which affected components matter most for your own software.
Quick check
Which bulletin item should I treat as the priority?
The CSRF flaw is rated 8.1, higher than this one. Both are fixed by the same PTF, so apply it and cover both.
Sources
- IBM security bulletin
- Safeguard Gold entry for CVE-2026-17075, which summarizes the NVD record
Last reviewed: 18 October 2026.
