CVE-2026-8858: IBM WebSphere Application Server and IBM WebSphere Application Server Liberty are vulnerable to remote code ex

Routine

HIGH 7.5UPGRADE

CVE-2026-8858 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 WebSphere Application Server and IBM WebSphere Application Server Liberty are vulnerable to remote code execution and denial of service in the WebSphere Web Server Plug-in component. This vulnerability can be exploited when an attacker impersonates the application server and sends crafted responses to the plug-in.

Why this priority

High severity

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Adjacent network
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	0.4% (top 65%)
CISA exploited list	No
Weakness	CWE-94
Published	2026-06-22
Last modified	2026-10-25

Publisher (CNA): IBM Corporation · Vendor: ibm

Last updated 2026-10-25 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-06-22 16:16 UTCPublished CVE record published
2026-10-25 23:10 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

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.

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-2026-8858?

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

Is CVE-2026-8858 being exploited?

CVE-2026-8858 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-2026-8858 affect?

CVE-2026-8858 affects i. Severity is high (CVSS 7.5). IBM WebSphere Application Server and IBM WebSphere Application Server Liberty are vulnerable to remote code execution and denial of service in the WebSphere Web Server Plug-in component. This vulnerability can be exploited when an attacker

How urgent is CVE-2026-8858?

Priority 35/100. High severity

Software pages

IBM WebSphere vulnerabilities

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References

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