CVE-2026-16987: IBM i 7.6, 7.5, 7.4, and 7.3 could allow a local attacker to gain elevated privileges due to improper validati

Routine

HIGH 8.8DOWNGRADE

CVE-2026-16987 is a high-severity flaw (CVSS 8.8) 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 local attacker to gain elevated privileges due to improper validation of the LANG environment variable.

Why this priority

High severity

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	8.8 (High)
Attack vector	Local
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.2% (top 96%)
CISA exploited list	No
Weakness	CWE-73
Published	2026-08-13
Last modified	2026-08-17

Publisher (CNA): IBM Corporation · Vendor: ibm

Last updated 2026-08-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-08-13 20:17 UTCPublished CVE record published
2026-08-17 14:42 UTCUpdated Record last modified

ibm i DOWNGRADE

Affected: 7.3 · 7.4 · 7.5 · 7.6

Fixed in: no fixed release known

Safe to downgrade to: a release before 7.3

1. Check installed version

apt-cache policy i || rpm -q i || i --version

2. No fixed release: 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

2. No fixed release: 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.

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.

Quick answers

How do I fix CVE-2026-16987?

i: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2026-16987 being exploited?

CVE-2026-16987 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-16987 affect?

CVE-2026-16987 affects i. Severity is high (CVSS 8.8). IBM i 7.6, 7.5, 7.4, and 7.3 could allow a local attacker to gain elevated privileges due to improper validation of the LANG environment variable.

How urgent is CVE-2026-16987?

Priority 32/100. High severity

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References

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