temporalio/sqlparser deeply nested unary expressions can cause a fatal stack overflow during AST traversal

Summary

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.

Timeline

1. Sep 21, 2026, 11:34 AM UTCCVE published
2. Sep 21, 2026, 3:30 PM UTCCISA SSVC assessment

   Exploitation: none · Automatable: no · Technical impact: partial

3. Sep 21, 2026, 3:31 PM UTCRecord last updated

Affected versions

• github.com/temporalio/sqlparser

  From 0.0.0-20141206041240-1aae9baceee8 · fixed in 0.0.0-20260721183058-0466b6b405ac

• go.temporal.io/server

  From 0.10.0 · through 1.29.7; From 1.30.0 · fixed in 1.30.7; From 1.31.0 · fixed in 1.31.3

References 9