CVE-2026-62357 dragonflydb CVE debrief

Who should care

Defenders responsible for Dragonfly deployments should assess exposure and prioritize patching to prevent potential memory corruption and server crashes. Operators of Dragonfly should review the vulnerability and take necessary actions to prevent exploitation. Platform administrators should ensure that the affected systems are patched or mitigated. Vulnerability management teams should prioritize patching and monitor for potential memory corruption and

Why it matters

CVE-2026-62357 is a high-severity vulnerability in Dragonfly that allows an unauthenticated remote client to corrupt or disclose adjacent heap memory and crash the server. Defenders should prioritize patching to prevent potential memory corruption and server crashes.

• Potential memory corruption and server crashes
• Possible disclosure of adjacent heap memory
• Need for patching to version 1.40.0 or later

Technical summary

The CMS.INITBYDIM and CMS.INITBYPROB commands in Dragonfly accept dimensions whose width times depth times sizeof(int64_t) overflows, allocating an undersized counter buffer. The CMS.INCRBY and CMS.QUERY commands use the unbounded dimensions, allowing an attacker to corrupt or disclose adjacent heap memory and crash the server. This issue is fixed in version 1.40.0. The vulnerability allows an unauthenticated remote client to corrupt or disclose adjacent heap memory and crash the server. Defenders should prioritize patching to prevent potential memory corruption and server crashes. The affected product deployments should be reviewed to assess exposure and prioritize patching.

Defensive priority

Defenders should prioritize patching to prevent potential memory corruption and server crashes.

Recommended defensive actions

• Patch Dragonfly to version 1.40.0 or later
• Restrict access to the affected commands
• Monitor for potential memory corruption and server crashes
• Review compensating controls for exposed systems while remediation is scheduled and verified
• Check relevant monitoring, detection, and logs for exposed assets that need extra review
• Track exceptions, retest remediated assets, and close the item only after evidence is documented
• Confirm whether affected product deployments exist in managed environments and assign an owner for follow-up

Evidence notes

The vulnerability is caused by the CMS.INITBYDIM and CMS.INITBYPROB commands accepting dimensions whose width times depth times sizeof(int64_t) overflows, allocating an undersized counter buffer. The CMS.INCRBY and CMS.QUERY commands use the unbounded dimensions, allowing an attacker to corrupt or disclose adjacent heap memory.

Sources and references

Methodology and review provenance

AI-assisted synthesis based on stored public vulnerability evidence. System validation, approval state, and publication status do not by themselves establish human review of this revision. PatchSiren helps prioritize defensive review and does not prove exposure or remediation on any system.