CVE-2026-33811

Name: CVE-2026-33811
Creator: NVD / NIST
Published: 2026-05-07T20:16:42.77+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.5/10EPSS 0.59%

Last modified Jun 17, 2026

CVE-2026-33811 is a high-severity vulnerability rated 7.5/10 on the CVSS scale. When using LookupCNAME with the cgo DNS resolver, a very long CNAME response can trigger a double-free of C memory and a crash.. EPSS estimates a 0.59% chance of exploitation in the next 30 days.

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.

Metrics

CVSS 3.1

7.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS Probability

0.59%

43.7th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-415

Affected Software

Vendor	Product	Versions
Golang	Go	< 1.25.10
Golang	Go	>= 1.26.0, < 1.26.3

References

https://go.dev/cl/767860Patch
https://go.dev/issue/78803Issue Tracking
https://groups.google.com/g/golang-announce/c/qcCIEXso47MMailing List, Third Party Advisory
https://pkg.go.dev/vuln/GO-2026-4981Vendor Advisory

Timeline

Published: May 7, 2026
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2026-33811?

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

How severe is CVE-2026-33811?

CVE-2026-33811 has a CVSS score of 7.5/10 (HIGH severity). The EPSS model estimates a 0.59% probability of exploitation in the next 30 days.

How do I fix CVE-2026-33811?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2026-33811?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST