CVE-2026-16908 is a high severity (CVSS 8.5) path traversal flaw in IBM i 7.3, 7.4, 7.5 and 7.6. A remote authenticated attacker could gain unauthorized access to arbitrary objects. IBM provides a PTF for each release under licensed program 5770-SS1, and the bulletin lists the numbers.
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:
- IBM i 7.6: SJ10871
- IBM i 7.5: SJ10835
- IBM i 7.4: SJ10840
- IBM i 7.3: SJ10841
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-22 is path traversal. A path supplied by a user is not confined to the directory it should stay in, so special path elements let the request escape. IBM says the result is unauthorized access to arbitrary objects. Scope is changed and impact is high on all three properties.
Attack complexity is rated high, which lowers the score a little. The same bulletin includes CVE-2026-16967, a symbolic link race with the same 8.5 score, so one PTF set closes both.
The weakness class here is CWE-22 (Path Traversal). The NVD record scores it 8.5, which is high severity. IBM's bulletin gives the same score. The CVSS vector reads attack vector over the network, high attack complexity, low privileges required, no user interaction. Scope is changed, meaning the impact can reach beyond the vulnerable component. Impact on confidentiality, integrity and availability is rated high, high and high. 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
Do both CVEs in this bulletin use the same PTF?
Yes. IBM lists one PTF per release in the bulletin. Verify that it is applied with DSPPTF.
Sources
- IBM security bulletin
- Safeguard Gold entry for CVE-2026-16908, which summarizes the NVD record
Last reviewed: 18 October 2026.
