GHSA-H599-M3W5-9M7X

Vulnerability from github – Published: 2026-10-30 23:00 – Updated: 2026-10-30 23:00
VLAI
Summary
MariaDB Connector/J: Rogue server can drive large heap allocations from server-declared lengths in OK packets
Details

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

Severity
5.9 (Medium)
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Show details on source website
To clipboard 

{
  "affected": [
    {
      "package": {
        "ecosystem": "Maven",
        "name": "org.mariadb.jdbc:mariadb-java-client"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "3.0.0"
            },
            {
              "fixed": "3.3.7"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Maven",
        "name": "org.mariadb.jdbc:mariadb-java-client"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "3.4.0"
            },
            {
              "fixed": "3.4.5"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    },
    {
      "package": {
        "ecosystem": "Maven",
        "name": "org.mariadb.jdbc:mariadb-java-client"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "3.5.0"
            },
            {
              "fixed": "3.5.11"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-119276"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-130",
      "CWE-789"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-10-30T23:00:12Z",
    "nvd_published_at": "2026-10-29T21:17:20Z",
    "severity": "MODERATE"
  },
  "details": "## Summary\n\nMariaDB Connector/J sized heap allocations from lengths declared by the server\nin OK packets before checking that those lengths fit in the packet. A rogue or\nMitM server can make the client allocate megabytes from a packet of a few bytes.\n\n## Details\n\nWhen `CLIENT_SESSION_TRACK` is negotiated (the default), an OK packet carries an\ninfo field followed by session-state blocks, each tracked variable being sent as a\nlength-encoded name and value. `OkPacket.parse()` and `parseWithInfo()` allocated\n`new byte[len]` for the info field, the variable name and the value with the\nserver-declared `len`, then copied the packet data into it. The copy failed with an\n`ArrayIndexOutOfBoundsException` when the packet was shorter, but only after the\nallocation had taken place.\n\nA server-declared length of 8 MiB in an 18-byte packet was enough to trigger an\n8 MiB allocation; the integer-range validation of length-encoded values does not\nhelp, since such lengths are valid positive integers.\n\nThe fix validates every server-declared length against the remaining packet bytes\nbefore any allocation (`ReadableByteBuf.checkLength()` and a bounded\n`readBytes(int)`), and stops reading the session state at the first inconsistent\nentry.\n\n## Impact\n\nAvailability only: a malicious or compromised server, or a MitM, can drive\nattacker-controlled heap allocations on every OK packet, creating GC pressure up to\n`OutOfMemoryError` in the client application. Exploitation requires control of the\nserver side of the connection; no authentication bypass, confidentiality or\nintegrity impact.\n\n## Credit\n\nReported by fg0x0",
  "id": "GHSA-h599-m3w5-9m7x",
  "modified": "2026-10-30T23:00:12Z",
  "published": "2026-10-30T23:00:12Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/mariadb-corporation/mariadb-connector-j/security/advisories/GHSA-h599-m3w5-9m7x"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-119276"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mariadb-corporation/mariadb-connector-j/commit/b9e1ee8d9b4d820d70719504cdfd5c97f1aede5f"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mariadb-corporation/mariadb-connector-j/commit/beb445fcf9294113878fc05ac77f0efdf0596ac6"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mariadb-corporation/mariadb-connector-j/commit/ea8c7b6537e50053444188a9a3fd9cae99550f56"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/mariadb-corporation/mariadb-connector-j"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mariadb-corporation/mariadb-connector-j/releases/tag/3.3.7"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mariadb-corporation/mariadb-connector-j/releases/tag/3.4.5"
    },
    {
      "type": "WEB",
      "url": "https://github.com/mariadb-corporation/mariadb-connector-j/releases/tag/3.5.11"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "MariaDB Connector/J: Rogue server can drive large heap allocations from server-declared lengths in OK packets"
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.




Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.

Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Vulnerability timeline

Sightings and recorded dates, grouped by day · UTC

JSON

Loading timeline…




    Related by attack behaviour

    Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.