Is CVE-2026-103223 exploited in the wild?

No. Junglewise Threat Intelligence has no report of CVE-2026-103223 being exploited in the wild.

How severe is CVE-2026-103223?

Medium severity, with a CVSS score of 5.9, published 15 October 2026.

Which products and versions are affected?

Eclipse Vertx-Pg-Client 4.0.0–4.5.34, 5.0.0–5.0.12, 5.1.0–5.1.9, 5.2.0.

Is there a fix for CVE-2026-103223?

Yes: fixed in vertx-pg-client 4.5.35, 5.1.10, 5.2.1. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

How is CVE-2026-103223 attacked?

It is attacked over the network.

Am I affected by CVE-2026-103223?

Check whether you run Eclipse Vert.X or Eclipse Vertx-Pg-Client at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

CVE-2026-103223: Eclipse Vert.x PostgreSQL client unbounded memory allocation

CVE-2026-103223 · Severity: medium · CVSS 5.9 · Published 2026-10-15

The Vert.x PostgreSQL client, a Java library for connecting applications to PostgreSQL databases, is vulnerable to denial of service when connecting to a malicious or compromised PostgreSQL server. An attacker can send a specially crafted message that causes the client to allocate unbounded memory, exhausting system resources and crashing the application before it even completes authentication.

Technologies: Eclipse Vert.X. Vendors: Eclipse.

Quick answers

Is CVE-2026-103223 exploited in the wild?: No. Junglewise Threat Intelligence has no report of CVE-2026-103223 being exploited in the wild.
How severe is CVE-2026-103223?: Medium severity, with a CVSS score of 5.9, published 15 October 2026.
Which products and versions are affected?: Eclipse Vertx-Pg-Client 4.0.0–4.5.34, 5.0.0–5.0.12, 5.1.0–5.1.9, 5.2.0.
Is there a fix for CVE-2026-103223?: Yes: fixed in vertx-pg-client 4.5.35, 5.1.10, 5.2.1. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
How is CVE-2026-103223 attacked?: It is attacked over the network.
Am I affected by CVE-2026-103223?: Check whether you run Eclipse Vert.X or Eclipse Vertx-Pg-Client at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

How to fix

Fixed in: vertx-pg-client 4.5.35, 5.1.10, 5.2.1

Technical details

The PostgreSQL wire protocol message decoder in vertx-pg-client fails to validate the maximum value of the 4-byte message length field, allowing a network attacker to specify arbitrarily large lengths (up to Integer.MAX_VALUE). The decoder then accumulates TCP data into a composite buffer without bounds, exhausting heap memory. This occurs before client authentication completes, requiring only network access to a PostgreSQL server endpoint.

Affected products

Eclipse vertx-pg-client 4.0.0–4.5.34, 5.0.0–5.0.12, 5.1.0–5.1.9, 5.2.0

Timeline

2026-10-15: disclosed
2026-10-07: advisory: GitHub Security Advisory published

References

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