Go/stdlib CVE-2026-39821: critical 9.6
Invoking failure to reject ASCII-only Punycode-encoded labels in golang.org/x/net/idna
Action: Upgrade stdlib to 1.25.13 or later.
Upgrade Go to 1.25.13.
Upgrade Go to 1.26.6.
Upgrade Go to 1.27.0-rc.3.
Affected
| introduced | fixed | last affected |
|---|---|---|
| 0 | 1.25.13 | - |
| 1.26.0-0 | 1.26.6 | - |
| 1.27.0-0 | - | - |
Fixed versions
| 1.25.13 | 1.26.6 | 1.27.0-rc.3 |
Sources
- osv: GO-2026-5026
- nvd: CVE-2026-39821
- https://go.dev/cl/767220
- https://go.dev/issue/78760
- https://groups.google.com/g/golang-announce/c/iI-mYSI0lu8
- https://groups.google.com/g/golang-announce/c/94pEornpRlI
CVE-2026-39821 · published · modified · JSON