High severity · published Jun 30, 2026
CVE-2026-50734
Apache ActiveMQ Client, Apache ActiveMQ, Apache ActiveMQ All: Pre-authentication OpenWire memory-allocation DoS during wire format negotiation
7.5
CVSS
0.7%
EPSS
No
On KEV
Description
Memory Allocation with Excessive Size Value vulnerability in Apache ActiveMQ Client, Apache ActiveMQ, Apache ActiveMQ All.
An unauthenticated network attacker can cause a broker DoS by sending a crafted WireFormatInfo frame with a malicious large size value. The value is not validate and causes the broker to attempt allocation during pre-auth negotiation which can trigger OOM and crash the broker.
This issue affects Apache ActiveMQ Client: before 5.19.8, from 6.0.0 before 6.2.7; Apache ActiveMQ: before 5.19.8, from 6.0.0 before 6.2.7; Apache ActiveMQ All: before 5.19.8, from 6.0.0 before 6.2.7.
Users are recommended to upgrade to version 6.2.7 or 5.19.8, which fixes the issue.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.7% · higher than 54% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
AC
ActiveMQ · Apache
before 5.19.8; 6.0.0 before 6.2.7 · source: vendor, NVD
AA
Apache ActiveMQ All · Apache Software Foundation
before 5.19.8; 6.0.0 before 6.2.7 · source: vendor
AA
Apache ActiveMQ Client · Apache Software Foundation
before 5.19.8; 6.0.0 before 6.2.7 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-50734
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-50734
Vendor Advisory
https://lists.apache.org/thread/nxso951fnvf72qf9m475mpz4yf931xk0
Third Party Advisory
http://www.openwall.com/lists/oss-security/2026/06/29/10
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