CVE-2026-100302
Allocation of Resources Without Limits or Throttling in the multiRead request handler of Apache ZooKeeper allows a remote attacker to crash the server (denial of service) with a single small request. The multiRead handler places no limit on the number of bundled read operations or on the cumulative size of the response it builds in memory. Because each operation's result is fully materialized and retained before serialization, a request that is small on the wire — within the jute.maxbuffer limit — but that references a large znode many times can force the server to allocate far more heap than the request size implies, exhausting the JVM heap and terminating the server with an OutOfMemoryError. Neither jute.maxbuffer nor largeRequestMaxBytes prevents this, as both bound only the inbound request, not the response. This issue affects Apache ZooKeeper from 3.7.0 through 3.9.6. Users are recommended to upgrade to version 3.9.7, which enforces configurable limits on the multiRead operation count and cumulative response size.
- Score
- 7.1 high
- Published
- 2026-11-04
- Links
- NVD · cve.org · Report wrong data
Matched ports (2)
| Port | Package | Version | Status | Maintainer |
|---|---|---|---|---|
| devel/libzookeeper | libzookeeper | 3.8.3 | unaddressed | ports@FreeBSD.org |
| devel/zookeeper | zookeeper | 3.8.3_2 | unaddressed | ports@FreeBSD.org |
Template for a VuXML entry
Check the version numbers before you commit this entry. Some ports share an entry in the CVE database with another port, such as sqlite2 and sqlite3. The version shown here may then be one that never existed for this port.
Ranges per package from the CVE rows that match this port, in pkg notation with the port's epoch and revision, every bound checked with pkg; one range per epoch the port actually had. make newentry in security/vuxml creates the vid.
<vuln vid="FIXME (make newentry)">
<topic>libzookeeper -- FIXME</topic>
<affects>
<package>
<name>libzookeeper</name>
<name>zookeeper</name>
<range><ge>3.8.0</ge><le>3.8.7</le></range>
</package>
</affects>
<description>
<body xmlns="http://www.w3.org/1999/xhtml">
<p>CVE-2026-100302: Allocation of Resources Without Limits or Throttling
in the multiRead request handler of Apache ZooKeeper allows a
remote attacker to crash the server (denial of service) with a
single small request. The multiRead handler places no limit on the
number of bundled read operations or on the cumulative size of the
response it builds in memory. Because each operation's result is
fully materialized and retained before serialization, a request
that is small on the wire — within the jute.maxbuffer limit — but
that references a large znode many times can force the server to
allocate far more heap than the request size implies, exhausting
the JVM heap and terminating the server with an OutOfMemoryError.
Neither jute.maxbuffer nor largeRequestMaxBytes prevents this, as
both bound only the inbound request, not the response. This issue
affects Apache ZooKeeper from 3.7.0 through 3.9.6. Users are
recommended to upgrade to version 3.9.7, which enforces
configurable limits on the multiRead operation count and cumulative
response size.</p>
</body>
</description>
<references>
<cvename>CVE-2026-100302</cvename>
<url>https://nvd.nist.gov/vuln/detail/CVE-2026-100302</url>
</references>
<dates>
<discovery>2026-11-04</discovery>
<entry>2026-11-04</entry>
</dates>
</vuln>