CVE-2026-33811

Description

When using LookupCNAME with the cgo DNS resolver, a very long CNAME response can trigger a double-free of C memory and a crash.

Affected packages (7)

• Bitnami/golangfrom 0, < 1.25.10, >= 1.26.0-0, < 1.26.3
• Debian/golang-1.15from 0
• Debian/golang-1.19from 0
• Debian/golang-1.24from 0
• Debian/golang-1.25from 0, < 1.25.10-1
• Debian/golang-1.26from 0, < 1.26.3-1
• Go/stdlibfrom 0, < 1.25.10, >= 1.26.0-0, < 1.26.3

CVSS scores

References (6)

• ADVISORYhttps://security-tracker.debian.org/tracker/CVE-2026-33811
• PATCHhttps://go.dev/cl/767860
• REPORThttps://go.dev/issue/78803
• WEBhttps://groups.google.com/g/golang-announce/c/qcCIEXso47M
• WEBhttps://nvd.nist.gov/vuln/detail/CVE-2026-33811
• WEBhttps://pkg.go.dev/vuln/GO-2026-4981