Axios CVE-2026-42037: Incident response steps for multipart header injection

CVE-2026-42037 is a CWE-93 flaw in Axios multipart bodies that affects versions from 1.0.0 up to but not including 1.15.1, with a CVSS 3.1 score of 5.3. The guidance urges responders to check whether an affected version was deployed, whether untrusted Blob metadata reached it, and whether a downstream parser acted on an injected header. Teams should gather request metadata and build details, then reproduce the issue locally against a vulnerable and a patched version without sending crafted requests to third parties or production systems. Logs should be reviewed for unexpected part headers, and each signal should be judged by whether it led to a consequential action rather than treated as proof of exploitation. The recommended remediation is upgrading to Axios 1.15.1 or later, with interim input validation at the upload boundary if immediate patching is not possible.