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 TCP data into a composite buffer without bound, leading to unbounded memory allocation on the client and an out-of-memory crash. This occurs before authentication completes.
The impacted component is io.vertx:vertx-pg-client.
{
"cna_assigner": "eclipse",
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/103xxx/CVE-2026-103223.json"
}{
"extracted_events": [
{
"introduced": "4.0.0"
},
{
"last_affected": "4.5.34"
},
{
"introduced": "5.0.0"
},
{
"last_affected": "5.0.12"
},
{
"introduced": "5.1.0"
},
{
"last_affected": "5.1.9"
},
{
"introduced": "5.2.0"
},
{
"last_affected": "5.2.0"
}
],
"source": "AFFECTED_FIELD"
}