CVE catalog

CVE-2026-39304

Denial of Service via Out of Memory vulnerability in…

[CVE catalog]

Denial of Service via Out of Memory vulnerability in Apache ActiveMQ Client, Apache ActiveMQ Broker, Apache ActiveMQ. ActiveMQ NIO SSL transports do not correctly handle TLSv1.3 handshake KeyUpdates triggered by clients. This makes it possible for a client to rapidly trigger updates which causes the broker to exhaust all its memory in the SSL engine leading to DoS. Note: TLS versions before TLSv1.3 (such as TLSv1.2) are broken but are not vulnerable to OOM. Previous TLS versions require a full handshake renegotiation which causes a connection to hang but not OOM. This is fixed as well. This issue affects Apache ActiveMQ Client: before 5.19.4, from 6.0.0 before 6.2.4; Apache ActiveMQ Broker: before 5.19.4, from 6.0.0 before 6.2.4; Apache ActiveMQ: before 5.19.4, from 6.0.0 before 6.2.4. Users are recommended to upgrade to version 6.2.4 or 5.19.5, which fixes the issue.

Severity
High · CVSS 7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published
Source
[NVD] · [CVE record]
EPSS
0.90% · Oct 27, 2026

Projects and upstream resources

Reported versions and fixes

Each observation applies to its named package, distribution, and release. Distribution backports can fix a vulnerability while retaining an older upstream version number.

Version impact has not been established. The original provider fields are retained below.

Provider details and historical evidence
Original provider fields
{
  "package_releases": [
    {
      "name": "activemq",
      "status": "vulnerable",
      "release": "sid",
      "version": "5.17.6+dfsg-2"
    },
    {
      "name": "activemq",
      "status": "vulnerable",
      "release": "trixie",
      "version": "5.17.6+dfsg-2"
    },
    {
      "name": "activemq",
      "status": "vulnerable",
      "release": "bookworm",
      "version": "5.17.2+dfsg-2+deb12u1"
    },
    {
      "name": "activemq",
      "status": "vulnerable",
      "release": "bookworm-security",
      "version": "5.17.2+dfsg-2+deb12u1"
    }
  ],
  "fixed_versions": [
    {
      "bug": 1136024,
      "name": "activemq",
      "type": "source",
      "origin": null,
      "release": "sid",
      "urgency": "not yet assigned",
      "fixed_version": ""
    },
    {
      "bug": 1136024,
      "name": "activemq",
      "type": "source",
      "origin": null,
      "release": "trixie",
      "urgency": "not yet assigned",
      "fixed_version": ""
    },
    {
      "bug": 1136024,
      "name": "activemq",
      "type": "source",
      "origin": null,
      "release": "bookworm",
      "urgency": "not yet assigned",
      "fixed_version": ""
    }
  ],
  "distribution_packages": [
    {
      "name": "activemq",
      "ecosystem": "cpe",
      "fixed_version": "not yet fixed"
    },
    {
      "name": "activemq",
      "ecosystem": "cpe",
      "fixed_version": "5.19.4"
    },
    {
      "name": "activemq",
      "ecosystem": "cpe",
      "fixed_version": "6.2.4"
    },
    {
      "name": "activemq_broker",
      "ecosystem": "cpe",
      "fixed_version": "5.19.4"
    },
    {
      "name": "activemq_broker",
      "ecosystem": "cpe",
      "fixed_version": "6.2.4"
    },
    {
      "name": "activemq",
      "ranges": [
        {
          "fixed": "6.2.4",
          "introduced": "6.0.0",
          "last_affected": "",
          "start_excluding": ""
        }
      ],
      "ecosystem": "cpe",
      "fixed_version": "6.2.4",
      "provider_record_id": "NVD-CVE-2026-39304"
    },
    {
      "name": "activemq_broker",
      "ranges": [
        {
          "fixed": "6.2.4",
          "introduced": "6.0.0",
          "last_affected": "",
          "start_excluding": ""
        }
      ],
      "ecosystem": "cpe",
      "fixed_version": "6.2.4",
      "provider_record_id": "NVD-CVE-2026-39304"
    }
  ]
}

[Debian bug #1136024]

OpenFactory catalog packages

Matching against OpenFactory catalog package versions is in progress.

[Debian 12 (Bookworm)]

  • [activemq]Unknown
    Details (4)

    • 5.17.2+dfsg-2+deb12u1 · all · bookworm

      Affected

      nvd · activemq · debian · bookworm; nvd · activemq · debian · 12

    • 5.17.2+dfsg-2+deb12u1 · all · bookworm

      Affected

      nvd · activemq · debian · bookworm; nvd · activemq · debian · 12

    • 5.17.2+dfsg-2+deb12u1 · all · bookworm-security

      Affected

      nvd · activemq · debian · bookworm; nvd · activemq · debian · 12

    • 5.17.2+dfsg-2+deb12u1 · all · bookworm-security

      Affected

      nvd · activemq · debian · bookworm; nvd · activemq · debian · 12

  • [libactivemq-java]Unknown

    Source package: [activemq]

    Details (4)

    • 5.17.2+dfsg-2+deb12u1 · all · bookworm

      Affected

      nvd · activemq · debian · bookworm; nvd · activemq · debian · 12

    • 5.17.2+dfsg-2+deb12u1 · all · bookworm

      Affected

      nvd · activemq · debian · bookworm; nvd · activemq · debian · 12

    • 5.17.2+dfsg-2+deb12u1 · all · bookworm-security

      Affected

      nvd · activemq · debian · bookworm; nvd · activemq · debian · 12

    • 5.17.2+dfsg-2+deb12u1 · all · bookworm-security

      Affected

      nvd · activemq · debian · bookworm; nvd · activemq · debian · 12

[Debian 13 (Trixie)]

  • [activemq]Unknown
    Details (2)

    • 5.17.6+dfsg-2 · all · trixie

      Affected

      nvd · activemq · debian · 13

    • 5.17.6+dfsg-2 · all · trixie

      Affected

      nvd · activemq · debian · 13

  • [libactivemq-java]Unknown

    Source package: [activemq]

    Details (2)

    • 5.17.6+dfsg-2 · all · trixie

      Affected

      nvd · activemq · debian · 13

    • 5.17.6+dfsg-2 · all · trixie

      Affected

      nvd · activemq · debian · 13

Observed:

References

[CERT-Bund public advisories] · [Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX]