CVE-2026-82631Public exploitNetwork attack vectorHinoki check available

Service crash via reentrant blocked-client iteration

Published Aug 31, 2026 · Updated Aug 31, 2026

Use-after-free in Valkey 9.1.0 allows remote authenticated users to crash the server through blocked-on-key module callbacks. handleClientsBlockedOnKey iterates a live blocked-client list while a synchronous module reply callback can kill and free the iterator's cached successor, which listNext then dereferences. Exploitation requires a loaded module whose callback kills another client blocked on the same ready key, and the bounded consequence is a valkey-server process crash.

CVSS severity2.2
Low
EPSS probability0.36%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Use-after-free in Valkey 9.1.0 allows remote authenticated users to crash the server through blocked-on-key module callbacks. handleClientsBlockedOnKey iterates a live blocked-client list while a synchronous module reply callback can kill and free the iterator's cached successor, which listNext then dereferences. Exploitation requires a loaded module whose callback kills another client blocked on the same ready key, and the bounded consequence is a valkey-server process crash.

The record

CVE
CVE-2026-82631
Published
Aug 31, 2026
Updated
Aug 31, 2026
Vendor
Valkey
Product
Valkey
Classifications
CWE-416, CWE-119, T1499.004
Attack vector
network
Privileges
admin

Timeline

How it unfolded

  1. Aug 31, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 31, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=9.1.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesadmin

What is affected?

Valkey · Valkeyversion=9.1.0

Published CVSS scores

2.2VulDB CNACVSS:3.1/AV:N/AC:H/PR:H/UI:N/S:U/C:N/I:N/A:L
2.1VulDB CNACVSS:4.0/AV:N/AC:H/AT:N/PR:H/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesadmin
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-416Use After Free
CWE-119Improper Restriction of Operations within the Bounds of a Memory Buffer
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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