Security readout for executives and security teams
Plain-English summary
CVE-2026-21697 affects axios4go, a Go HTTP client library. In versions before 0.6.4, concurrent requests can interfere with shared client settings. Applications using different proxy settings across simultaneous requests may send traffic using the wrong configuration, risking sensitive data exposure or unintended routing. The vendor released version 0.6.4 to fix it.
Executive priority
Treat as a high-priority dependency update for affected Go services handling sensitive outbound traffic. Urgency is highest where concurrent requests and proxy separation are security controls. If axios4go is not used, there is no direct exposure from this CVE.
Technical view
axios4go before 0.6.4 has a CWE-362 race condition in its global defaultClient. During request execution, shared http.Client fields including Transport, Timeout, and CheckRedirect are mutated without synchronization. Impact is most relevant for concurrent goroutine usage, async helpers, and mixed proxy configurations. CVSS 4.0 score is 8.2 high.
Likely exposure
Exposure is likely limited to Go applications that import axios4go versions earlier than 0.6.4 and perform concurrent requests, especially with per-request proxy differences or sensitive credentials, tokens, or API keys in outbound traffic.
Exploitation context
The provided sources do not report active exploitation, and this CVE is not marked as KEV. Practical risk depends on whether an application uses concurrent axios4go requests and varying request configuration. The weakness is configuration leakage through a race condition, not a standalone remote code execution issue.
Researcher notes
Key evidence comes from the GitHub advisory, CVE record, fix commit, and v0.6.4 release. The advisory states the vulnerable shared defaultClient is mutated without synchronization. No public source in the bundle confirms exploitation in the wild. Validate exposure by dependency version and concurrency/proxy usage patterns.
Mitigation direction
- Upgrade axios4go to version 0.6.4 or later.
- Prioritize services using concurrent requests or async axios4go helpers.
- Review applications that use different proxy configurations per request.
- Check vendor advisory and release notes for implementation details.
Validation and detection
- Inventory Go modules for github.com/rezmoss/axios4go versions below 0.6.4.
- Identify code paths using GetAsync, PostAsync, or multiple goroutines.
- Review outbound proxy handling for mixed per-request configurations.
- Confirm dependency lockfiles and builds use axios4go 0.6.4 or later.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-362: Exact CWE lookup
Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2026-21697 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- High
- CVSS
- 8.2 (4.0)
- Known Exploited
- No
- Published
Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N——Primary CVE scoreVulnerability scoring details
Base CVSS 4.0 score
8.2HighVector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/rezmoss/axios4go/security/advisories/GHSA-cmj9-27wj-7x47CVE reference · x_refsource_CONFIRM
- https://github.com/rezmoss/axios4go/commit/b651604c64e66a115ab90cdab358b0181d74a842CVE reference · x_refsource_MISC
- https://github.com/rezmoss/axios4go/releases/tag/v0.6.4CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')
Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.