CVE-2026-103223: In Eclipse Vert.x versions [4.0.0, 4.5.34] or [5.0.0,5.0.12] or [5.1.0,5.1.9] or [5.2.0, 5.2.0], the PostgreSQ

Routine

MEDIUM 5.9REMOTEUPGRADE

CVE-2026-103223 is a medium-severity flaw (CVSS 5.9) affecting vert.x. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

In Eclipse Vert.x versions [4.0.0, 4.5.34] or [5.0.0,5.0.12] or [5.1.0,5.1.9] or [5.2.0, 5.2.0], the PostgreSQL message decoder reads the 4-byte message length field from the PostgreSQL wire protocol without any maximum validation. A malicious, compromised, or man-in-the-middle PostgreSQL server can send a message header with the length field set to an extremely large value (up to Integer.MAX_VALUE), causing the decoder to accumulate subsequent T

Why this priority

Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	5.9 (Medium)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	0.3% (top 75%)
CISA exploited list	No
Weakness	CWE-789
Published	2026-10-15
Last modified	2026-10-20

Publisher (CNA): Eclipse Foundation · Vendor: eclipse

Last updated 2026-10-20 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-10-15 09:17 UTCPublished CVE record published
2026-10-20 19:25 UTCUpdated Record last modified

eclipse vert.x UPGRADE

Affected: >= 4.5.0 and < 4.5.35 · >= 5.0.0 and < 5.1.10 · 5.2.0

Fixed in: 4.5.35, 5.1.10

Safe to downgrade to: a release before 4.5.0

1. Check installed version

apt-cache policy vert.x || rpm -q vert.x || vert.x --version

2. UPGRADE to 4.5.35 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade vert.x

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade vert.x

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 4.5.0 (Debian / Ubuntu)

apt-cache madison vert.x sudo apt install vert.x=<VERSION_BEFORE_4.5.0> sudo apt-mark hold vert.x

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

dnf --showduplicates list vert.x sudo dnf downgrade vert.x-<VERSION_BEFORE_4.5.0> sudo dnf versionlock add vert.x

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-2026-103223?

vert.x: upgrade to 4.5.35, 5.1.10. Exact commands for each OS are on this page.

Is CVE-2026-103223 being exploited?

CVE-2026-103223 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-2026-103223 affect?

CVE-2026-103223 affects vert.x. Severity is medium (CVSS 5.9). In Eclipse Vert.x versions [4.0.0, 4.5.34] or [5.0.0,5.0.12] or [5.1.0,5.1.9] or [5.2.0, 5.2.0], the PostgreSQL message decoder reads the 4-byte message length field from the PostgreSQL wire protocol without any maximum validation. A malici

How urgent is CVE-2026-103223?

Priority 32/100. Remotely exploitable, no login, no user action

Software pages

PostgreSQL vulnerabilities

Related CVEs

CVE-2026-15075 HIGH 7.5 UPGRADE In Eclipse Vert.x versions up to and including 4.5.29 (4.x branch) and 5.1.4 (5.x branch), DefaultRedirectHand
CVE-2026-15076 HIGH 7.5 UPGRADE In versions up to and including 4.5.29 (4.x branch) and 5.1.4 (5.x branch), the WebClientSession component of
CVE-2026-102471 MEDIUM 5.9 UPGRADE In Eclipse Vert.x versions [4.0.0, 4.5.34] or [5.0.0,5.0.12] or [5.1.0,5.1.9] or [5.2.0, 5.2.0], the vertx-mai
CVE-2026-102479 MEDIUM 5.9 UPGRADE In Eclipse Vert.x versions [5.0.0,5.0.12] or [5.1.0,5.1.9] or [5.2.0, 5.2.0], the Vert.x HTTP/1.x decoder uses
CVE-2026-102465 MEDIUM 5.9 UPGRADE In Eclipse Vert.x versions [4.0.0, 4.5.34] or [5.0.0,5.0.12] or [5.1.0,5.1.9] or [5.2.0, 5.2.0], the Vert.x Re

References

← Back to latest CVEs