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CVE-2026-21863— Malformed Valkey Cluster bus message can lead to Remote DoS

Quick assessment

Affected
valkey-io valkey
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.

Valkey是Valkey开源的一个灵活的分布式键值数据库。 Valkey 9.0.2之前版本、8.1.6之前版本、8.0.7之前版本和7.2.12之前版本存在缓冲区错误漏洞，该漏洞源于集群总线数据包处理代码未验证扩展数据包位置，可能导致越界读取和系统崩溃。

CVSS 7.5 · High EPSS 0.85% · P58

Possible ATT&CK Techniques 1 AI

T1190 · Exploit Public-Facing Application

Affected Version Matrix 4

VendorProduct Version RangeStatus
valkey-io valkey < 7.2.12 affected
>= 8.0.0, < 8.0.7 affected
>= 8.1.0, < 8.1.6 affected
>= 9.0.0, < 9.0.2 affected
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I. Basic Information for CVE-2026-21863

Vulnerability Information
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Vulnerability Title
Malformed Valkey Cluster bus message can lead to Remote DoS
Source: CVE Program / CVE List V5
Vulnerability Description
Valkey is a distributed key-value database. Prior to versions 9.0.2, 8.1.6, 8.0.7, and 7.2.12, a malicious actor with access to the Valkey clusterbus port can send an invalid packet that may cause an out bound read, which might result in the system crashing. The Valkey clusterbus packet processing code does not validate that a clusterbus ping extension packet is located within buffer of the clusterbus packet before attempting to read it. Versions 9.0.2, 8.1.6, 8.0.7, and 7.2.12 fix the issue. As an additional mitigation, don't expose the cluster bus connection directly to end users, and protect the connection with its own network ACLs.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
跨界内存读
Source: CVE Program / CVE List V5
Vulnerability Title
Valkey 缓冲区错误漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Valkey是Valkey开源的一个灵活的分布式键值数据库。 Valkey 9.0.2之前版本、8.1.6之前版本、8.0.7之前版本和7.2.12之前版本存在缓冲区错误漏洞，该漏洞源于集群总线数据包处理代码未验证扩展数据包位置，可能导致越界读取和系统崩溃。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
valkey-io valkey < 7.2.12 -

II. Public POCs for CVE-2026-21863

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III. Intelligence Information for CVE-2026-21863

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Same Patch Batch · valkey-io · 2026-02-23 · 3 CVEs total

CVE-2025-67733 8.5 HIGH Valkey Affected by RESP Protocol Injection via Lua error_reply
CVE-2026-27623 7.5 HIGH Valkey has Pre-Authentication DOS from malformed RESP request

IV. Related Vulnerabilities

Same product: valkey
Same vendor: valkey-io
Same weakness: CWE-125