PatchTheCVECVE-2026-16931: IBM i 7.6, 7.5, 7.4, and 7.3 could allow a remote attacker to cause a denial of service due to improper handli
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HIGH 7.5REMOTEUPGRADE
CVE-2026-16931 is a high-severity flaw (CVSS 7.5) affecting i. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
IBM i 7.6, 7.5, 7.4, and 7.3 could allow a remote attacker to cause a denial of service due to improper handling of zero-length TCP options.
Why this priority
- High severity
- Remotely exploitable, no login, no user action
A fixed release or distro patch exists.
Risk facts
| CVSS score | 7.5 (High) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 0.5% (top 55%) |
| CISA exploited list | No |
| Weakness | CWE-835 |
| Published | 2026-08-12 |
| Last modified | 2026-10-23 |
Publisher (CNA): IBM Corporation · Vendor: ibm
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
ibm i UPGRADE
Affected: >= 7.3 and <= 7.6
Fixed in: newer than 7.6
Safe to downgrade to: a release before 7.3
1. Check installed version
apt-cache policy i || rpm -q i || i --version
2. UPGRADE to newer than 7.6 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade i
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade i
Note
Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.
3. If no update is available yet, DOWNGRADE to a release before 7.3 (Debian / Ubuntu)
apt-cache madison i
sudo apt install i=<VERSION_BEFORE_7.3>
sudo apt-mark hold i
3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list i
sudo dnf downgrade i-<VERSION_BEFORE_7.3>
sudo dnf versionlock add i
Downgrade risk
Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.
After downgrade
Restart the service, and keep the package held until a fixed release ships.
Exact fixes by distribution
Fedora 46 · clementine · FIXED · 1.4.2-1.fc46 · FEDORA-2026-3e748ef4d3 · source
sudo dnf upgrade --advisory=FEDORA-2026-3e748ef4d3
Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
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