CVE-2026-33811
Crash when handling long CNAME response in net
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.
INFO
Published Date :
May 7, 2026, 8:16 p.m.
Last Modified :
May 12, 2026, 8:23 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | ||||
| CVSS 3.1 | HIGH | [email protected] |
Solution
- Update the DNS resolver to handle long CNAME responses correctly.
- Apply patches addressing the double-free memory issue.
- Test DNS resolution with extended CNAME records.
Public PoC/Exploit Available at Github
CVE-2026-33811 has a 2 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-33811.
| URL | Resource |
|---|---|
| https://go.dev/cl/767860 | Patch |
| https://go.dev/issue/78803 | Issue Tracking |
| https://groups.google.com/g/golang-announce/c/qcCIEXso47M | Mailing List Third Party Advisory |
| https://pkg.go.dev/vuln/GO-2026-4981 | Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-33811 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-33811
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
None
HCL Shell
This project provides a simple example of Spring Boot CRUD application with Postgres DB, docker-compose and LGTM Observability support
docker docker-compose grafana jdbc lgtm-stack makefile postgres spring-boot
Makefile Shell Dockerfile Java
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-33811 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-33811 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
May. 12, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Added CWE CWE-415 Added CPE Configuration OR *cpe:2.3:a:golang:go:*:*:*:*:*:*:*:* versions up to (excluding) 1.25.10 *cpe:2.3:a:golang:go:*:*:*:*:*:*:*:* versions from (including) 1.26.0 up to (excluding) 1.26.3 Added Reference Type Go Project: https://go.dev/cl/767860 Types: Patch Added Reference Type Go Project: https://go.dev/issue/78803 Types: Issue Tracking Added Reference Type Go Project: https://groups.google.com/g/golang-announce/c/qcCIEXso47M Types: Mailing List, Third Party Advisory Added Reference Type Go Project: https://pkg.go.dev/vuln/GO-2026-4981 Types: Vendor Advisory -
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
May. 08, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H -
New CVE Received by [email protected]
May. 07, 2026
Action Type Old Value New Value Added 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. Added Reference https://go.dev/cl/767860 Added Reference https://go.dev/issue/78803 Added Reference https://groups.google.com/g/golang-announce/c/qcCIEXso47M Added Reference https://pkg.go.dev/vuln/GO-2026-4981