CVE-2026-4942: IBM i 7.6, 7.5, 7.4, and 7.3 could allow a remote attacker to send a specifically crafted message and downgrad

Routine

MEDIUM 5.9REMOTEMITIGATE

CVE-2026-4942 is a medium-severity flaw (CVSS 5.9) 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 send a specifically crafted message and downgrade the Transport Layer Security (TLS) protocol to a version disabled in the server configuration.

Why this priority

Remotely exploitable, no login, no user action

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

Risk facts

CVSS score	5.9 (Medium)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	0.4% (top 64%)
CISA exploited list	No
Weakness	CWE-757
Published	2026-07-17
Last modified	2026-10-24

Publisher (CNA): IBM Corporation · Vendor: ibm

Last updated 2026-10-24 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-17 20:17 UTCPublished CVE record published
2026-10-24 20:10 UTCUpdated Record last modified

ibm i MITIGATE

Affected: 7.3 · 7.4 · 7.5 · 7.6

Fixed in: no fixed release known

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-2026-4942?

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

Is CVE-2026-4942 being exploited?

CVE-2026-4942 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-2026-4942 affect?

CVE-2026-4942 affects i. Severity is medium (CVSS 5.9). IBM i 7.6, 7.5, 7.4, and 7.3 could allow a remote attacker to send a specifically crafted message and downgrade the Transport Layer Security (TLS) protocol to a version disabled in the server configuration.

How urgent is CVE-2026-4942?

Priority 35/100. Remotely exploitable, no login, no user action

Related CVEs

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CVE-2026-17095 HIGH 8.3 MITIGATE IBM i 7.6, 7.5, 7.4, and 7.3 could allow a remote authenticated attacker to bypass security restrictions due t
CVE-2026-18847 HIGH 8.8 MITIGATE IBM i 7.6, 7.5, 7.4, and 7.3 could allow a remote unauthenticated attacker to harvest credentials due to spoof
CVE-2026-18098 HIGH 8.1 MITIGATE IBM i 7.6, 7.5, 7.4, and 7.3 could allow a remote authenticated attacker to obtain sensitive information and c
CVE-2026-16694 MEDIUM 6.4 MITIGATE IBM i 7.6, 7.5, 7.4, and 7.3 is vulnerable to stored cross-site scripting

References

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