Server crash via self-stopping module timer
Published Aug 31, 2026 · Updated Aug 31, 2026
Double free in Valkey 9.1.0 Module Timer Subsystem allows remote attackers to crash the server through a self-stopping timer callback. VM_StopTimer removes and frees the firing timer when its callback stops itself, but moduleTimerHandler retains the stale pointer and frees it again after the callback returns. The server must load a module exposing this callback behavior; invoking its command then causes a reproducible process abort and service interruption.
Summary
What happened
Double free in Valkey 9.1.0 Module Timer Subsystem allows remote attackers to crash the server through a self-stopping timer callback. VM_StopTimer removes and frees the firing timer when its callback stops itself, but moduleTimerHandler retains the stale pointer and frees it again after the callback returns. The server must load a module exposing this callback behavior; invoking its command then causes a reproducible process abort and service interruption.
The record
- CVE
- CVE-2026-82677
- Published
- Aug 31, 2026
- Updated
- Aug 31, 2026
- Vendor
- Valkey
- Product
- Valkey
- Classifications
- CWE-415, T1499.004
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Aug 31, 2026CVE publishedPublication date reported by the CVE source.
- 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.
- Affected versionversion=9.1.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
No CVSS assessment is available in this record.
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.
Public exploit references
- Module timer self-stop PoCproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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