Security incident · CVE-2026-119276

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

Q: Which versions are affected?

Compare what you have installed with 3.0.0 → 3.3.7, 3.4.0 → 3.4.5, 3.5.0 → 3.5.11, >= 3.0.0, = 3.4.0, = 3.5.0, < 3.5.11. Compare the installed version with the linked vendor advisory before you change production.

Q: What should an analyst verify?

CWE-130; CWE-789. EPSS 0.35%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Published Oct 30, 2026 · catalog updated Oct 30, 2026 · MariaDB Connector/J: Rogue server

Last checked Oct 31, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2026-119276. EPSS is 0.35%. Act only if a listed version of MariaDB Connector/J: Rogue server is installed.

Gaps on this record

The stored product name is a package slug. The name on this page is taken from the title (MariaDB Connector/J: Rogue server).
No vendor fix or required action is stored. Compare the linked advisory before you change production.

Severity: Medium5.9
Known exploitation: Not in CISA/VulnCheck KEV
EPSS: 0.35%
Remediation: Version ranges on file
Affected products: Maven org.mariadb.jdbc:mariadb-java-client · maven org.mariadb.jdbc · maven org.mariadb.jdbc:mariadb-java-client

## 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 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. and allocated for the info field, the variable name and the value with the server-declared , then copied the packet data into it. The copy failed with an 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 ( and a bounded ), 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 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

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

Maven org.mariadb.jdbc:mariadb-java-client3.0.0 → 3.3.7
Maven org.mariadb.jdbc:mariadb-java-client3.4.0 → 3.4.5
Maven org.mariadb.jdbc:mariadb-java-client3.5.0 → 3.5.11
maven org.mariadb.jdbcversion unspecified
maven org.mariadb.jdbc:mariadb-java-client>= 3.0.0, < 3.3.7
maven org.mariadb.jdbc:mariadb-java-client>= 3.4.0, < 3.4.5
maven org.mariadb.jdbc:mariadb-java-client>= 3.5.0, < 3.5.11

How to fix CVE-2026-119276

Upgrade
CVE-2026-119276 lists a fix boundary at 3.3.7. Compare the installed build with that boundary before you change production.
Version check
Affected < 3.3.7
Advisory
Open the cve_org record and follow its fix.
Official advisories

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-119276. EPSS is 0.35%. Act only if a listed version of MariaDB Connector/J: Rogue server is installed.

Which versions are affected?

Compare what you have installed with 3.0.0 → 3.3.7, 3.4.0 → 3.4.5, 3.5.0 → 3.5.11, >= 3.0.0, < 3.3.7, >= 3.4.0, < 3.4.5, >= 3.5.0, < 3.5.11. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-130; CWE-789. EPSS 0.35%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

MariaDB security

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

Oct 30, 2026 · GitHub Advisory Database
Detected
## 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 is negotiated (the default), an OK packet carries an info field followed by session-state blocks, each tracked variable being sent as
Oct 30, 2026 · GitHub Advisory Database
Fix available
org.mariadb.jdbc:mariadb-java-client fixed in 3.3.7; org.mariadb.jdbc:mariadb-java-client fixed in 3.4.5; org.mariadb.jdbc:mariadb-java-client fixed in 3.5.11
Oct 30, 2026 · GitHub Advisory Database
Fix available
org.mariadb.jdbc:mariadb-java-client fixed in 3.3.7
Oct 30, 2026 · GitHub Advisory Database
Fix available
org.mariadb.jdbc:mariadb-java-client fixed in 3.4.5
Oct 30, 2026 · GitHub Advisory Database
Fix available
org.mariadb.jdbc:mariadb-java-client fixed in 3.5.11
Oct 30, 2026 · GitHub Advisory Database
Updated
## 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 is negotiated (the default), an OK packet carries an info field followed by session-state blocks, each tracked variable being sent as

Sources

CVE.orgVulnerability recordCVE-2026-119276
Official CVE identifier
cve.org
GitHub Advisory DatabasePackage advisoryGHSA-h599-m3w5-9m7x
MariaDB Connector/J: Rogue server can drive large heap allocations from server-declared lengths in OK packets
github.com
GitLab Advisory DatabasePackage advisoryCVE-2026-119276
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.
advisories.gitlab.com
OpenSSF OSV / OSV ScannerPackage advisoryGHSA-h599-m3w5-9m7x
MariaDB Connector/J: Rogue server can drive large heap allocations from server-declared lengths in OK packets
osv.dev

References

Freshness

Last verified in this catalog Oct 31, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

CVE.orgOct 31, 2026
GitLab Advisory DatabaseOct 31, 2026
GitHub Advisory DatabaseOct 31, 2026
OpenSSF OSV / OSV ScannerOct 31, 2026

Priority score

10/100

Evidence confidence: High

Several independent sources name this vulnerability.

Confirmed exploitation0/30
EPSS probability1/20
CVSS severity9/15
Public exploit0/10
Internet exposure0/10
Product prevalence0/5
Detection0/5
Threat research0/5

Decision signals

Four separate signals — do not infer one from another.

Medium

CVSS severity
5.9 v3.1
Technical impact. Separate from exploitation likelihood.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS probability
0.35% · p28.74%
Estimated probability of exploitation within 30 days (FIRST).
Known exploitation
No verified KEV listing
Evidence from CISA KEV or VulnCheck KEV only — not from EPSS alone.
Patch availability
Version ranges on file
Affected version ranges suggest a fixed boundary. Verify against the vendor advisory for your release.

Stacks

MariaDB Maven

Weakness

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