CVE-2026-66909: Apache CXF's JMS transport deserializes the body of any inbound JMS ObjectMessage using native Java deserializ

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CRITICAL 9.8REMOTEWATCHLISTUPGRADE

CVE-2026-66909 is a critical-severity flaw (CVSS 9.8) affecting cxf. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Apache CXF's JMS transport deserializes the body of any inbound JMS ObjectMessage using native Java deserialization, with no type restrictions in place. Any attacker able to place a message on the service's JMS destination can submit a malicious serialized object, leading to denial of service or, if a suitable gadget class is on the classpath, remote code execution. The fix disables ObjectMessage deserialization by default, with a configuration s

Why this priority

Critical severity
CISA SSVC: automatable with total technical impact
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.1% (top 33%)
CISA exploited list	No
Weakness	CWE-502
Published	2026-08-06
Last modified	2026-10-23

Publisher (CNA): Apache Software Foundation · Vendor: apache

Last updated 2026-10-23 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-08-06 11:16 UTCPublished CVE record published
2026-10-23 21:10 UTCUpdated Record last modified

apache cxf UPGRADE

Affected: < 3.6.12 · >= 4.0.0 and < 4.1.8 · >= 4.2.0 and < 4.2.3

Fixed in: 3.6.12, 4.1.8, 4.2.3

Safe to downgrade to: a release before 4.0.0

1. Check installed version

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

2. UPGRADE to 3.6.12 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade cxf

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade cxf

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 4.0.0 (Debian / Ubuntu)

apt-cache madison cxf sudo apt install cxf=<VERSION_BEFORE_4.0.0> sudo apt-mark hold cxf

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list cxf sudo dnf downgrade cxf-<VERSION_BEFORE_4.0.0> sudo dnf versionlock add cxf

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.

Exact fixes by distribution

Fedora 46 · pspp · FIXED · 2.1.3-2.fc46 · FEDORA-2026-0d6444911b · source

sudo dnf upgrade --advisory=FEDORA-2026-0d6444911b

Fedora ELN · barman · FIXED · 3.20.1-3.eln159 · FEDORA-2026-45ecf042c2 · source

sudo dnf upgrade --advisory=FEDORA-2026-45ecf042c2

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-2026-66909?

cxf: upgrade to 3.6.12, 4.1.8, 4.2.3. Exact commands for each OS are on this page.

Is CVE-2026-66909 being exploited?

CVE-2026-66909 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-2026-66909 affect?

CVE-2026-66909 affects cxf. Severity is critical (CVSS 9.8). Apache CXF's JMS transport deserializes the body of any inbound JMS ObjectMessage using native Java deserialization, with no type restrictions in place. Any attacker able to place a message on the service's JMS destination can submit a mali

How urgent is CVE-2026-66909?

Priority 64/100. Critical severity; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Java vulnerabilities

Related CVEs

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References

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