CVE-2026-33811
HIGH severity · CVSS 7.5 · Double free
7.5CVSS HIGH
Summary
When using LookupCNAME with the cgo DNS resolver, a very long CNAME response can trigger a double-free of C memory and a crash.
Impact & exploitability
Attack vectorNetwork
Attack complexityLow
Privileges requiredNone
User interactionNone
Confidentiality impactNone
Integrity impactNone
Availability impactHigh
Exploit probability (EPSS)1%
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Affected products we track (1)
Recommendation
Apply the vendor fix promptly. Open any affected product above for its exact safe version.
Official patch: https://go.dev/cl/767860 ↗
Additional information
- NVD record
- https://go.dev/cl/767860Patch
- https://pkg.go.dev/vuln/GO-2026-4981Advisory
- https://go.dev/issue/78803
- https://groups.google.com/g/golang-announce/c/qcCIEXso47MAdvisory
- https://access.redhat.com/errata/RHSA-2026:23262
- https://access.redhat.com/errata/RHSA-2026:23264
- https://access.redhat.com/errata/RHSA-2026:33120
- https://access.redhat.com/errata/RHSA-2026:33123