CVE-2026-40046
Apache ActiveMQ, Apache ActiveMQ All, Apache ActiveMQ MQTT: Missing fix for CVE-2025-66168: MQTT control packet remaining length field is not properly validated
CVE-2026-40046 is a high vulnerability (CVSS 7.5) in Apache Software Foundation Activemq, published April 9, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.38%, the 31st percentile. Fixed in org.apache.activemq:apache-activemq 6.2.4.
Integer Overflow or Wraparound vulnerability in Apache ActiveMQ, Apache ActiveMQ All, Apache ActiveMQ MQTT.
The fix for "CVE-2025-66168: MQTT control packet remaining length field is not properly validated" was only applied to 5.19.2 (and future 5.19.x) releases but was missed for all 6.0.0+ versions.
This issue affects Apache ActiveMQ: from 6.0.0 before 6.2.4; Apache ActiveMQ All: from 6.0.0 before 6.2.4; Apache ActiveMQ MQTT: from 6.0.0 before 6.2.4.
Users are recommended to upgrade to version 6.2.4 or a 5.19.x version starting with 5.19.2 or later (currently latest is 5.19.5), which fixes the issue.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
7.5
Apache ActiveMQ, Apache ActiveMQ All, Apache ActiveMQ MQTT: Missing fix for CVE-2025-66168: MQTT control packet remaining length field is not properly validated
Integer Overflow or Wraparound vulnerability in Apache ActiveMQ, Apache ActiveMQ All, Apache ActiveMQ MQTT.
The fix for "CVE-2025-66168: MQTT control packet remaining length field is not properly validated" was only applied to 5.19.2 (and future 5.19.x) releases but was missed for all 6.0.0+ versions.
This issue affects Apache ActiveMQ: from 6.0.0 before 6.2.4; Apache ActiveMQ All: from 6.0.0 before 6.2.4; Apache ActiveMQ MQTT: from 6.0.0 before 6.2.4.
Users are recommended to upgrade to version 6.2.4 or a 5.19.x version starting with 5.19.2 or later (currently latest is 5.19.5), which fixes the issue.
- Record
CVE-2026-40046- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-190
- Updated
- 2026-11-02
EUVDEUVD-2026-20956
7.5
Integer Overflow or Wraparound vulnerability in Apache ActiveMQ, Apache ActiveMQ All, Apache ActiveMQ MQTT.
The fix for "CVE-2025-66168: MQTT control packet remaining length field is not properly validated" was only applied to 5.19.2 (and future 5.19.x) releases but was missed for all 6.0.0+ versions.
This issue affects Apache ActiveMQ: from 6.0.0 before 6.2.4; Apache ActiveMQ All: from 6.0.0 before 6.2.4; Apache ActiveMQ MQTT: from 6.0.0 before 6.2.4.
Users are recommended to upgrade to version 6.2.4 or a 5.19.x version starting with 5.19.2 or later (currently latest is 5.19.5), which fixes the issue.
- Record
EUVD-2026-20956- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-xvqc-pp94-fmpx
5.4
Apache ActiveMQ, Apache ActiveMQ All, Apache ActiveMQ MQTT vulnerable to Integer Overflow or Wraparound
Integer Overflow or Wraparound vulnerability in Apache ActiveMQ, Apache ActiveMQ All, Apache ActiveMQ MQTT.
The fix for "CVE-2025-66168: MQTT control packet remaining length field is not properly validated" was only applied to 5.19.2 (and future 5.19.x) releases but was missed for all 6.0.0+ versions. This issue affects Apache ActiveMQ: from 6.0.0 before 6.2.4; Apache ActiveMQ All: from 6.0.0 before 6.2.4; Apache ActiveMQ MQTT: from 6.0.0 before 6.2.4.
Users are recommended to upgrade to version 6.2.4 or a 5.19.x version starting with 5.19.2 or later (currently latest is 5.19.5), which fixes the issue.
- Record
GHSA-xvqc-pp94-fmpx- CVSS 3.1
- 5.4 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N - Weakness
- CWE-190
- Updated
- 2026-11-02
NVD
7.5
Integer Overflow or Wraparound vulnerability in Apache ActiveMQ, Apache ActiveMQ All, Apache ActiveMQ MQTT.
The fix for "CVE-2025-66168: MQTT control packet remaining length field is not properly validated" was only applied to 5.19.2 (and future 5.19.x) releases but was missed for all 6.0.0+ versions.
This issue affects Apache ActiveMQ: from 6.0.0 before 6.2.4; Apache ActiveMQ All: from 6.0.0 before 6.2.4; Apache ActiveMQ MQTT: from 6.0.0 before 6.2.4.
Users are recommended to upgrade to version 6.2.4 or a 5.19.x version starting with 5.19.2 or later (currently latest is 5.19.5), which fixes the issue.
- Record
CVE-2026-40046- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Weakness
- CWE-190
- Updated
- 2026-11-02
OSVGHSA-xvqc-pp94-fmpx
5.4
Apache ActiveMQ, Apache ActiveMQ All, Apache ActiveMQ MQTT vulnerable to Integer Overflow or Wraparound
Integer Overflow or Wraparound vulnerability in Apache ActiveMQ, Apache ActiveMQ All, Apache ActiveMQ MQTT.
The fix for "CVE-2025-66168: MQTT control packet remaining length field is not properly validated" was only applied to 5.19.2 (and future 5.19.x) releases but was missed for all 6.0.0+ versions. This issue affects Apache ActiveMQ: from 6.0.0 before 6.2.4; Apache ActiveMQ All: from 6.0.0 before 6.2.4; Apache ActiveMQ MQTT: from 6.0.0 before 6.2.4.
Users are recommended to upgrade to version 6.2.4 or a 5.19.x version starting with 5.19.2 or later (currently latest is 5.19.5), which fixes the issue.
- Record
GHSA-xvqc-pp94-fmpx- CVSS 3.1
- 5.4 Medium
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:L/A:N - Weakness
- CWE-190
- Updated
- 2026-11-02
OSVOESA-2026-2124
8.8
activemq security update
The most popular and powerful open source messaging and Integration Patterns server.
Security Fix(es):
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…
- Record
OESA-2026-2124- CVSS 3.1
- 8.8 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
Show 6 moreShow less
OSVOESA-2026-2125
8.8
activemq security update
The most popular and powerful open source messaging and Integration Patterns server.
Security Fix(es):
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…
- Record
OESA-2026-2125- CVSS 3.1
- 8.8 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVOESA-2026-2126
8.8
activemq security update
The most popular and powerful open source messaging and Integration Patterns server.
Security Fix(es):
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…
- Record
OESA-2026-2126- CVSS 3.1
- 8.8 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVOESA-2026-2127
8.8
activemq security update
The most popular and powerful open source messaging and Integration Patterns server.
Security Fix(es):
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…
- Record
OESA-2026-2127- CVSS 3.1
- 8.8 High
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVUBUNTU-CVE-2026-40046
7.5
Integer Overflow or Wraparound vulnerability in Apache ActiveMQ, Apache ActiveMQ All, Apache ActiveMQ MQTT. The fix for "CVE-2025-66168: MQTT control packet remaining length field is not properly validated" was only applied to 5.19.2 (and future 5.19.x) releases but was missed for all 6.0.0+ versions. This issue affects Apache ActiveMQ: from 6.0.0 before 6.2.4; Apache ActiveMQ All: from 6.0.0 before 6.2.4; Apache ActiveMQ MQTT: from 6.0.0 before 6.2.4. Users are recommended to upgrade to version 6.2.4 or a 5.19.x version starting with 5.19.2 or later (currently latest is 5.19.5), which fixes the issue.
- Record
UBUNTU-CVE-2026-40046- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - Updated
- 2026-11-02
OSVBIT-activemq-2026-40046 No score
Apache ActiveMQ, Apache ActiveMQ All, Apache ActiveMQ MQTT: Missing fix for CVE-2025-66168: MQTT control packet remaining length field is not properly validated
Integer Overflow or Wraparound vulnerability in Apache ActiveMQ, Apache ActiveMQ All, Apache ActiveMQ MQTT.
The fix for "CVE-2025-66168: MQTT control packet remaining length field is not properly validated" was only applied to 5.19.2 (and future 5.19.x) releases but was missed for all 6.0.0+ versions.
This issue affects Apache ActiveMQ: from 6.0.0 before 6.2.4; Apache ActiveMQ All: from 6.0.0 before 6.2.4; Apache ActiveMQ MQTT: from 6.0.0 before 6.2.4.
Users are recommended to upgrade to version 6.2.4 or a 5.19.x version starting with 5.19.2 or later (currently latest is 5.19.5), which fixes the issue.
- Record
BIT-activemq-2026-40046- Updated
- 2026-11-02
OSVROOT-APP-MAVEN-CVE-2026-40046 No score
CVE-2026-40046 in io.root.org.apache.activemq:activemq-all - Patched by Root
Root has patched CVE-2026-40046 in the io.root.org.apache.activemq:activemq-all package for Root:Maven. Multiple fixed versions available.
- Record
ROOT-APP-MAVEN-CVE-2026-40046- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
org.apache.activemq:apache-activemqMaven |
6.0.0 up to 6.2.4 | 6.2.4 |
org.apache.activemq:activemq-allMaven |
6.0.0 up to 6.2.4 | 6.2.4 |
org.apache.activemq:activemq-mqttMaven |
6.0.0 up to 6.2.4 | 6.2.4 |
activemqBitnami |
6.0.0 up to 6.2.4 | 6.2.4 |
org.apache.activemq:apache-activemqMaven |
6.0.0 up to 6.2.4, plus listed versions 6.0.16.1.06.1.16.1.26.1.3 Show 9 moreShow less6.1.46.1.56.1.66.1.76.1.86.2.06.2.16.2.26.2.3 |
6.2.4 |
org.apache.activemq:activemq-allMaven |
6.0.0 up to 6.2.4, plus listed versions 6.0.16.1.06.1.16.1.26.1.3 Show 9 moreShow less6.1.46.1.56.1.66.1.76.1.86.2.06.2.16.2.26.2.3 |
6.2.4 |
org.apache.activemq:activemq-mqttMaven |
6.0.0 up to 6.2.4, plus listed versions 6.0.16.1.06.1.16.1.26.1.3 Show 9 moreShow less6.1.46.1.56.1.66.1.76.1.86.2.06.2.16.2.26.2.3 |
6.2.4 |
activemqopenEuler:22.03-LTS-SP4 |
before 5.19.6-1.oe2203sp4 | 5.19.6-1.oe2203sp4 |
activemqopenEuler:24.03-LTS |
before 5.19.6-1.oe2403 | 5.19.6-1.oe2403 |
activemqopenEuler:24.03-LTS-SP1 |
before 5.19.6-1.oe2403sp1 | 5.19.6-1.oe2403sp1 |
Show 13 moreShow less
| Package | Affected | Fixed |
|---|---|---|
activemqopenEuler:24.03-LTS-SP3 |
before 5.19.6-1.oe2403sp3 | 5.19.6-1.oe2403sp3 |
io.root.org.apache.activemq:activemq-allRoot:Maven |
before 6.1.3-root.io.5 | 6.1.3-root.io.56.1.3-root.io.66.1.3-root.io.76.1.3-root.io.8 |
io.root.org.apache.activemq:activemq-mqttRoot:Maven |
before 6.1.3-root.io.5 | 6.1.3-root.io.56.1.3-root.io.66.1.3-root.io.76.1.3-root.io.8 |
org.apache.activemq:activemq-allRoot:Maven |
before 6.1.3-aikido.5 | 6.1.3-aikido.56.1.3-aikido.66.1.3-aikido.76.1.3-aikido.8 |
org.apache.activemq:activemq-mqttRoot:Maven |
before 6.1.3-aikido.5 | 6.1.3-aikido.56.1.3-aikido.66.1.3-aikido.76.1.3-aikido.8 |
activemqUbuntu:Pro:16.04:LTS |
All versions, plus listed versions 5.6.0+dfsg1-4+deb8u1ubuntu15.6.0+dfsg1-55.13.2+dfsg-25.13.2+dfsg-2ubuntu0.1~esm1 |
None known |
activemqUbuntu:Pro:18.04:LTS |
All versions, plus listed versions 5.14.5-35.15.2-25.15.3-25.15.8-2~18.045.15.8-2~18.04.1~esm1 |
None known |
activemqUbuntu:Pro:20.04:LTS |
All versions, plus listed versions 5.15.10-15.15.11-15.15.11-1ubuntu0.1~esm1 |
None known |
activemqUbuntu:Pro:22.04:LTS |
All versions, plus listed versions 5.16.1-15.16.1-1ubuntu0.1~esm15.16.1-1ubuntu0.1 |
None known |
activemqUbuntu:24.04:LTS |
All versions, plus listed versions 5.17.2+dfsg-25.17.6+dfsg-1 |
None known |
activemqUbuntu:25.10 |
All versions, plus listed versions 5.17.6+dfsg-15.17.6+dfsg-2 |
None known |
activemqUbuntu:26.10 |
All versions, plus listed versions 5.17.6+dfsg-25.17.6+dfsg-2ubuntu1 |
None known |
activemqUbuntu:26.04:LTS |
All versions, plus listed versions 5.17.6+dfsg-2 |
None known |
History
| When | Changed | Sources |
|---|---|---|
| 2026-11-02 | created | CVE List, EUVD, GitHub Advisories, NVD, OSV |
References
cve.org/CVERecord?id=CVE-2025-66168
activemq.apache.org/security-advisories.data/CVE-2026-40046-announcement.txt
lists.apache.org/thread/zdntj5rcgjjzrpow84o339lzldy68zrg
nvd.nist.gov/vuln/detail/CVE-2026-40046
github.com/advisories/GHSA-xvqc-pp94-fmpx
openeuler.org/zh/security/security-bulletins/detail?id=openEuler-SA-2026-2124
Show 11 moreShow less
nvd.nist.gov/vuln/detail/CVE-2026-33227
nvd.nist.gov/vuln/detail/CVE-2026-34197
nvd.nist.gov/vuln/detail/CVE-2026-39304
nvd.nist.gov/vuln/detail/CVE-2026-40466
nvd.nist.gov/vuln/detail/CVE-2026-41043
nvd.nist.gov/vuln/detail/CVE-2026-41044
openeuler.org/zh/security/security-bulletins/detail?id=openEuler-SA-2026-2125
openeuler.org/zh/security/security-bulletins/detail?id=openEuler-SA-2026-2126
openeuler.org/zh/security/security-bulletins/detail?id=openEuler-SA-2026-2127
ubuntu.com/security/CVE-2026-40046
cve.org/CVERecord?id=CVE-2026-40046
Left out here: the rest of 4 source descriptions. The JSON record has them.