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CVE-2026-100302— Apache ZooKeeper: Denial of service through unbounded memory allocation in multiRead request handling

Quick assessment

Affected
Apache Software Foundation Apache ZooKeeper
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Apache ZooKeeper 的 请求处理器中存在“无限制或无流量控制的资源分配”漏洞，允许远程攻击者通过单个小型请求导致服务器崩溃（拒绝服务）。 处理器未对捆绑的读取操作数量或其构建的内存中响应累积大小设置任何限制。由于每个操作的结果在序列化之前都会被完全实例化并保留，因此即使网络传输中的请求很小（在 限制之内），若该请求多次引用大型 znode，也可能迫使服务器分配远超请求本身大小的堆内存，最终耗尽 JVM 堆空间并引发 导致服务器终止。 和 均无法防止此问题，因为两者仅限制入站请求的大小，而不限制响应的大

CVSS 7.1 · High

Possible ATT&CK Techniques 1 AI

T1499 · Endpoint Denial of Service
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I. Basic Information for CVE-2026-100302

Vulnerability Information
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Vulnerability Title
Apache ZooKeeper: Denial of service through unbounded memory allocation in multiRead request handling
Source: CVE Program / CVE List V5
Vulnerability Description
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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Source: CVE Program / CVE List V5
Vulnerability Type
不加限制或调节的资源分配
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
Apache Software Foundation Apache ZooKeeper 3.9.0 ~ 3.9.6 -

II. Public POCs for CVE-2026-100302

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III. Intelligence Information for CVE-2026-100302

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Other References for CVE-2026-100302 (1)

Same Patch Batch · Apache Software Foundation · 2026-11-04 · 23 CVEs total

CVE-2026-100300 8.7 HIGH Apache ZooKeeper: Unauthenticated persistent denial of service via unvalidated quota-node
CVE-2026-115448 8.7 HIGH Apache ZooKeeper: Unbounded recursion in snapshot serialization allows a client to render
CVE-2026-100252 8.6 HIGH Apache ZooKeeper: SASL authorization bypass on the client port through a client-supplied a
CVE-2026-100235 6.0 MEDIUM Apache ZooKeeper: ACL enforcement bypass allows unauthorized operations to commit after an
CVE-2026-59267 5.8 MEDIUM Apache OpenOffice: Heap Buffer Overflow in DXF LWPOLYLINE import could cause memory corrup
CVE-2026-59263 1.9 LOW Apache OpenOffice: Carefully crafted documents could display different data when opened wi
CVE-2026-59264 Apache OpenOffice: Uncontrolled search path element vulnerability in Windows installer
CVE-2026-90632 Apache OpenOffice: Local file inclusion via GStreamer plugin
CVE-2026-90634 Apache OpenOffice: Out-of-bounds write when importing encrypted PDF files
CVE-2026-90631 Apache OpenOffice: Remote document loaded without prompt, possibiy leaking environment var
CVE-2026-90629 Apache OpenOffice: Out of bounds memory access during WMF import
CVE-2026-90628 Apache OpenOffice: Stack overflow in CFF hint handling
CVE-2026-90627 Apache OpenOffice: Local file inclusion via SQL provider and flat file database references
CVE-2026-90626 Apache OpenOffice: Out-of-bounds write when importing encrypted PDF files
CVE-2026-90624 Apache OpenOffice: PDF File Parsing Heap based Buffer-Overflow-Remote Code Execution Vulne
CVE-2026-59268 Apache OpenOffice: Heap out-of-bounds write in WW8 PLCF reader
CVE-2026-108949 Apache ActiveMQ, ActiveMQ Broker: Repeated rejected temporary destination consumer request
CVE-2026-108500 Apache ActiveMQ: LDAPAuthorizationMap allows authorization bypass via DN injection
CVE-2026-103582 Apache ActiveMQ NMS OpenWire Client Library: Unbounded/Unvalidated Length Fields in Apache
CVE-2026-108946 Apache ActiveMQ, ActiveMQ Broker: The broker does not verify user provided connection id m

Showing top 20 of 23 CVEs. View all on vendor page → →

IV. Related Vulnerabilities

Same product: Apache ZooKeeper
Same vendor: Apache Software Foundation
Same weakness: CWE-770