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CVE-2026-9330: IBM WebSphere Application Server 9.0, and 8.5 is affected by an improper validation of user-supplied data duri

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HIGH 8.5UPGRADE

CVE-2026-9330 is a high-severity flaw (CVSS 8.5) affecting websphere application server. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

IBM WebSphere Application Server 9.0, and 8.5 is affected by an improper validation of user-supplied data during deserialization using the SAML Web Single Sign-On component. This could result in remote code execution via a crafted HTTP request when combined with a suitable gadget chain.

Why this priority

  • High severity

A fixed release or distro patch exists.

Risk facts

CVSS score8.5 (High)
Attack vectorNetwork (remote)
Attack complexityHigh
Privileges neededLow
User interactionNone
EPSS exploit chance0.5% (top 56%)
CISA exploited listNo
WeaknessCWE-502
Published2026-06-01
Last modified2026-07-22
Publisher (CNA): IBM Corporation · Vendor: ibm

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Last updated 2026-07-22 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

ibm websphere application server UPGRADE
Affected: >= 8.5.0.0 and < 8.5.5.30 · >= 9.0.0.0 and < 9.0.5.29
Fixed in: 8.5.5.30, 9.0.5.29
Safe to downgrade to: a release before 8.5.0.0
1. Check installed version
apt-cache policy websphere-application-server || rpm -q websphere-application-server || websphere-application-server --version
2. UPGRADE to 8.5.5.30 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade websphere-application-server
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade websphere-application-server
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 8.5.0.0 (Debian / Ubuntu)
apt-cache madison websphere-application-server sudo apt install websphere-application-server=<VERSION_BEFORE_8.5.0.0> sudo apt-mark hold websphere-application-server
3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list websphere-application-server sudo dnf downgrade websphere-application-server-<VERSION_BEFORE_8.5.0.0> sudo dnf versionlock add websphere-application-server
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-2026-9330?

websphere application server: upgrade to 8.5.5.30, 9.0.5.29. Exact commands for each OS are on this page.

Is CVE-2026-9330 being exploited?

CVE-2026-9330 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-2026-9330 affect?

CVE-2026-9330 affects websphere application server. Severity is high (CVSS 8.5). IBM WebSphere Application Server 9.0, and 8.5 is affected by an improper validation of user-supplied data during deserialization using the SAML Web Single Sign-On component. This could result in remote code execution via a crafted HTTP requ

How urgent is CVE-2026-9330?

Priority 41/100. High severity

Software pages

IBM WebSphere vulnerabilities

Related CVEs

References

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