CVE-2026-21697: rezmoss axios4go · Race Condition
Affects rezmoss axios4goSource CVE Database V5
Not known to be exploited · CVSS 8.2 High : upgrade to 0.6.4 soon.
Data as of 25 Oct 2026, 19:02 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 34% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 0.6.4
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 7 Jan 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-25.
What to do
Upgrade axios4go and github.com/rezmoss/axios4go to 0.6.4.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| rezmossaxios4go | Affected
| Fixed in
|
Gogithub.com/rezmoss/axios4gopkg:golang/github.com/rezmoss/axios4goOther threats | Affected
| Fixed in
|
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AI-suggested
1. Upgrade axios4go to version 0.6.4 or later immediately to ensure the race condition is fixed. 2. Audit all Go applications using axios4go to identify concurrent HTTP client usage patterns, especially where different proxy or authentication configurations are applied per request. 3. Refactor code to avoid sharing mutable global HTTP client configurations across goroutines without proper synchronization primitives such as mutexes or by using separate client instances per configuration. 4. Implement rigorous testing for concurrent request handling to detect race conditions using Go's race detector tool. 5. Monitor application logs for anomalies in HTTP client behavior or unexpected credential exposure. 6. Educate development teams on safe concurrent programming practices in Go, emphasizing immutable or properly synchronized shared state. 7. Review and tighten access controls and network segmentation to limit exposure of vulnerable services until patched. 8. Maintain an inventory of all internal and third-party Go libraries to quickly identify and remediate similar concurrency issues.
Description
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.