CVE-2026-63639Network attack vector

Use-after-free via shared NACK deserialization

Published Aug 18, 2026 · Updated Aug 20, 2026

Use-after-free in Valkey before 7.2.14, 8.0.10, 8.1.9, 9.0.5, and 9.1.1 allows remote authenticated users to trigger memory corruption via RESTORE. During stream consumer-group deserialization, the RDB loader assigns a Pending Entry List NACK to a consumer without ensuring that the NACK is unassigned, so a malformed payload can make multiple consumers share one NACK and leave a dangling reference when one consumer is deleted. Exploitation requires the ability to issue RESTORE, and Valkey states that the resulting shared-NACK use-after-free can lead to remote code execution.

CVSS severity8.8
High
EPSS probability0.89%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Valkey before 7.2.14, 8.0.10, 8.1.9, 9.0.5, and 9.1.1 allows remote authenticated users to trigger memory corruption via RESTORE. During stream consumer-group deserialization, the RDB loader assigns a Pending Entry List NACK to a consumer without ensuring that the NACK is unassigned, so a malformed payload can make multiple consumers share one NACK and leave a dangling reference when one consumer is deleted. Exploitation requires the ability to issue RESTORE, and Valkey states that the resulting shared-NACK use-after-free can lead to remote code execution.

The record

CVE
CVE-2026-63639
Published
Aug 18, 2026
Updated
Aug 20, 2026
Vendor
Valkey
Product
Valkey
Classifications
CWE-416
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Aug 18, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 20, 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=< 7.2.14
  2. Affected versionversion=>= 8.0.0, < 8.0.10
  3. Affected versionversion=>= 8.1.0, < 8.1.9
  4. Affected versionversion=>= 9.0.0, < 9.0.5
  5. Affected versionversion=>= 9.1.0, < 9.1.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Valkey · Valkeyversion=< 7.2.14; version=>= 8.0.0, < 8.0.10; version=>= 8.1.0, < 8.1.9; version=>= 9.0.0, < 9.0.5; version=>= 9.1.0, < 9.1.1

Published CVSS scores

8.8GitHub Security AdvisoryCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-416Use After Free

Public exploit references

No public exploit references are available in this record.

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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