Go net/mail EUVD-2026-28423

Upgrade to Go 1.26.3 or Go 1.25.10 which contain fixes for the resource exhaustion issue in net/mail parsing functions. Recompile all affected applications with the patched Go version to incorporate the standard library fix. For applications that cannot immediately upgrade, implement rate limiting on email parsing operations to restrict the number of ParseAddress, ParseAddressList, and ParseDate calls per client or time window (trade-off: legitimate high-volume email processing may be impacted). Deploy resource constraints using cgroups or container limits to cap CPU and memory consumption for processes handling email parsing (trade-off: may cause parsing failures under legitimate load spikes). Consider input validation to reject email addresses or date strings exceeding reasonable length thresholds before passing to parsing functions (trade-off: may block legitimate but unusual RFC 5322-compliant formats). Vendor advisory: https://groups.google.com/g/golang-announce/c/qcCIEXso47M. Patch implementation details: https://go.dev/cl/759940.