CVE-2026-21697: Rezmoss AXIOS4GO

High severity, CVSS 8.1. EPSS: 0.4% chance of exploitation in the next 30 days.

axios4go is a Go HTTP client library. Prior to version 0.6.4, a race condition vulnerability exists in the shared HTTP client configuration. The global `defaultClient` is mutated during request execution without synchronization, directly modifying the shared `http.Client`'s `Transport`, `Timeout`, and `CheckRedirect` properties. Impacted applications include that that use axios4go with concurrent requests (multiple goroutines, `GetAsync`, `PostAsync`, etc.), those where different requests use different proxy configurations, and those that handle sensitive data (authentication credentials, tokens, API keys). Version 0.6.4 fixes this issue.

Affected products

• Rezmoss AXIOS4GO: before 0.6.4 (fixed in 0.6.4)

Published 2026-01-07. Last modified 2026-06-17.