CVE-2026-81858: IBM i 7.3, 7.4, 7.5, and 7.6 could allow a remote authenticated attacker to cause a denial of service and obta

Q: How do I fix CVE-2026-81858?

i: upgrade to newer than 7.6. Exact commands for each OS are on this page.

Q: Is CVE-2026-81858 being exploited?

CVE-2026-81858 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-81858 affect?

CVE-2026-81858 affects i. Severity is medium (CVSS 5.4). IBM i 7.3, 7.4, 7.5, and 7.6 could allow a remote authenticated attacker to cause a denial of service and obtain information due to an out-of-bounds read in the File Server.

Q: How urgent is CVE-2026-81858?

Priority 24/100. No elevated risk signals yet.

Routine

MEDIUM 5.4UPGRADE

CVE-2026-81858 is a medium-severity flaw (CVSS 5.4) affecting i. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

IBM i 7.3, 7.4, 7.5, and 7.6 could allow a remote authenticated attacker to cause a denial of service and obtain information due to an out-of-bounds read in the File Server.

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	5.4 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.3% (top 80%)
CISA exploited list	No
Weakness	CWE-125
Published	2026-10-13
Last modified	2026-10-14

Publisher (CNA): IBM Corporation · Vendor: ibm

Last updated 2026-10-14 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-10-13 00:17 UTCPublished CVE record published
2026-10-14 23:48 UTCUpdated 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

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

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-2026-81858?

i: upgrade to newer than 7.6. Exact commands for each OS are on this page.

Is CVE-2026-81858 being exploited?

CVE-2026-81858 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-2026-81858 affect?

CVE-2026-81858 affects i. Severity is medium (CVSS 5.4). IBM i 7.3, 7.4, 7.5, and 7.6 could allow a remote authenticated attacker to cause a denial of service and obtain information due to an out-of-bounds read in the File Server.

How urgent is CVE-2026-81858?

Priority 24/100. No elevated risk signals yet.

Related CVEs

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CVE-2026-10852 MEDIUM 5.9 MITIGATE IBM WebSphere Application Server and IBM WebSphere Application Server Liberty are vulnerable to denial of serv
CVE-2026-8858 HIGH 7.5 UPGRADE IBM WebSphere Application Server and IBM WebSphere Application Server Liberty are vulnerable to remote code ex
CVE-2026-4942 MEDIUM 5.9 MITIGATE IBM i 7.6, 7.5, 7.4, and 7.3 could allow a remote attacker to send a specifically crafted message and downgrad

References

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