Unauthenticated heap corruption via CMS overflow
Published Aug 18, 2026 · Updated Aug 19, 2026
Integer overflow in Dragonfly Count-Min Sketch initialization before 1.40.0 allows remote attackers to corrupt memory via crafted dimensions. CMS.INITBYDIM and CMS.INITBYPROB pass width and depth into src/core/cms.cc, where width × depth × sizeof(int64_t) can wrap size_t, allocate too few counters, and leave CMS.INCRBY and CMS.QUERY indexing the unbounded sketch. Any client that can reach the service can trigger out-of-bounds writes and reads without authentication, disclosing adjacent heap data or terminating the server process.
Summary
What happened
Integer overflow in Dragonfly Count-Min Sketch initialization before 1.40.0 allows remote attackers to corrupt memory via crafted dimensions. CMS.INITBYDIM and CMS.INITBYPROB pass width and depth into src/core/cms.cc, where width × depth × sizeof(int64_t) can wrap size_t, allocate too few counters, and leave CMS.INCRBY and CMS.QUERY indexing the unbounded sketch. Any client that can reach the service can trigger out-of-bounds writes and reads without authentication, disclosing adjacent heap data or terminating the server process.
The record
- CVE
- CVE-2026-62357
- Published
- Aug 18, 2026
- Updated
- Aug 19, 2026
- Vendor
- DragonflyDB
- Product
- Dragonfly
- Classifications
- CWE-190, T1190, T1499
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 18, 2026CVE publishedPublication date reported by the CVE source.
- Aug 19, 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=< 1.40.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
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.
Weakness, pattern, technique
Public exploit references
- GHSA-cmmv-h748-v93x proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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