---
id: CVE-2026-119276
aliases:
  - GHSA-h599-m3w5-9m7x
title: >-
  MariaDB Connector/J: Rogue server can drive large heap allocations from
  server-declared lengths in OK packets
summary: >-
  MariaDB Connector/J: Rogue server can drive large heap allocations from
  server-declared lengths in OK packets
severity: medium
cvss: 5.9
cwe:
  - CWE-130
  - CWE-789
vendor: mariadb
product: 'org.mariadb.jdbc:mariadb-java-client'
ecosystem: maven
affected:
  - 'org.mariadb.jdbc:mariadb-java-client >= 3.0.0, < 3.3.7'
  - 'org.mariadb.jdbc:mariadb-java-client >= 3.4.0, < 3.4.5'
  - 'org.mariadb.jdbc:mariadb-java-client >= 3.5.0, < 3.5.11'
patched:
  - 'org.mariadb.jdbc:mariadb-java-client 3.3.7'
  - 'org.mariadb.jdbc:mariadb-java-client 3.4.5'
  - 'org.mariadb.jdbc:mariadb-java-client 3.5.11'
published: '2026-10-30'
updated: '2026-10-30'
sourceUpdated: '2026-10-30T23:00:14Z'
source: GHSA
sourceUrl: 'https://github.com/advisories/GHSA-h599-m3w5-9m7x'
references:
  - url: >-
      https://github.com/mariadb-corporation/mariadb-connector-j/security/advisories/GHSA-h599-m3w5-9m7x
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-119276'
  - url: >-
      https://github.com/mariadb-corporation/mariadb-connector-j/commit/b9e1ee8d9b4d820d70719504cdfd5c97f1aede5f
  - url: >-
      https://github.com/mariadb-corporation/mariadb-connector-j/commit/beb445fcf9294113878fc05ac77f0efdf0596ac6
  - url: >-
      https://github.com/mariadb-corporation/mariadb-connector-j/commit/ea8c7b6537e50053444188a9a3fd9cae99550f56
  - url: >-
      https://github.com/mariadb-corporation/mariadb-connector-j/releases/tag/3.3.7
  - url: >-
      https://github.com/mariadb-corporation/mariadb-connector-j/releases/tag/3.4.5
  - url: >-
      https://github.com/mariadb-corporation/mariadb-connector-j/releases/tag/3.5.11
  - url: 'https://github.com/advisories/GHSA-h599-m3w5-9m7x'
tags:
  - ghsa
  - maven
epss: 0.00351
epssPercentile: 0.28744
ingestedAt: '2026-10-30T23:11:25.780Z'
---

## Overview

## Summary

MariaDB Connector/J sized heap allocations from lengths declared by the server
in OK packets before checking that those lengths fit in the packet. A rogue or
MitM server can make the client allocate megabytes from a packet of a few bytes.

## Details

When `CLIENT_SESSION_TRACK` is negotiated (the default), an OK packet carries an
info field followed by session-state blocks, each tracked variable being sent as a
length-encoded name and value. `OkPacket.parse()` and `parseWithInfo()` allocated
`new byte[len]` for the info field, the variable name and the value with the
server-declared `len`, then copied the packet data into it. The copy failed with an
`ArrayIndexOutOfBoundsException` when the packet was shorter, but only after the
allocation had taken place.

A server-declared length of 8 MiB in an 18-byte packet was enough to trigger an
8 MiB allocation; the integer-range validation of length-encoded values does not
help, since such lengths are valid positive integers.

The fix validates every server-declared length against the remaining packet bytes
before any allocation (`ReadableByteBuf.checkLength()` and a bounded
`readBytes(int)`), and stops reading the session state at the first inconsistent
entry.

## Impact

Availability only: a malicious or compromised server, or a MitM, can drive
attacker-controlled heap allocations on every OK packet, creating GC pressure up to
`OutOfMemoryError` in the client application. Exploitation requires control of the
server side of the connection; no authentication bypass, confidentiality or
integrity impact.

## Credit

Reported by fg0x0

## Affected packages

- `org.mariadb.jdbc:mariadb-java-client >= 3.0.0, < 3.3.7`
- `org.mariadb.jdbc:mariadb-java-client >= 3.4.0, < 3.4.5`
- `org.mariadb.jdbc:mariadb-java-client >= 3.5.0, < 3.5.11`

## Remediation

Upgrade to a patched release:

- `org.mariadb.jdbc:mariadb-java-client 3.3.7`
- `org.mariadb.jdbc:mariadb-java-client 3.4.5`
- `org.mariadb.jdbc:mariadb-java-client 3.5.11`