CVE-2026-65651: temporal technologies, inc. temporal server Uncontrolled Recursion

Vulnerability summary

CVE-2026-65651 is a high (CVSS 8.7) Uncontrolled Recursion vulnerability in temporal technologies, inc. temporal server. EPSS estimates a 0.67% chance of exploitation in the next 30 days, higher than 51.2% of scored vulnerabilities.

Timeline

1. 21-09-2026
   PublishedVulnerability first disclosed.
2. 21-09-2026
   Last modifiedVulnerability information updated.

Description

temporalio/sqlparser accepts SQL containing deeply nested unary expressions and can return a correspondingly deep abstract syntax tree without enforcing an applicable nesting limit. The library's String and Walk operations recursively traverse that tree. An application that parses attacker-controlled SQL and later formats or walks the returned tree can encounter a runtime-fatal Go stack overflow that terminates the process; Go panic recovery cannot contain this condition. Temporal Server passes caller-controlled query input through the affected parser in archival, visibility, and worker-query paths. In affected validation paths, the Server recursively formats an invalid expression while constructing an error. In a supported authenticated deployment, a caller with namespace read permission can terminate the receiving Frontend or Matching process. The dynamically confirmed ListWorkers route additionally requires at least one retained worker heartbeat. Repeated requests can sustain a denial of service. The issue affects availability only; no confidentiality or integrity impact was identified.

• CWE-674Uncontrolled RecursionThe product does not properly control the amount of recursion that takes place, consuming excessive resources, such as allocated memory or the program stack.