net up to 1.25.9/1.26.2 on Go cgo DNS Resolver LookupCNAME double free

CVSS Meta Temp Score
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CTI Interest Score
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6.2$0-$5k0.00

Summaryinfo

A vulnerability labeled as problematic has been found in net up to 1.25.9/1.26.2 on Go. This affects the function LookupCNAME of the component cgo DNS Resolver. Such manipulation leads to double free. This vulnerability is uniquely identified as CVE-2026-33811. The attack can be launched remotely. No exploit exists. The affected component should be upgraded.

Detailsinfo

A vulnerability was found in net up to 1.25.9/1.26.2 on Go. It has been rated as problematic. Affected by this issue is the function LookupCNAME of the component cgo DNS Resolver. The manipulation with an unknown input leads to a double free vulnerability. Using CWE to declare the problem leads to CWE-415. The product calls free() twice on the same memory address, potentially leading to modification of unexpected memory locations. Impacted is availability. CVE summarizes:

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

The advisory is shared for download at go.dev. This vulnerability is handled as CVE-2026-33811 since 03/23/2026. The exploitation is known to be difficult. The attack may be launched remotely. No form of authentication is required for exploitation. There are known technical details, but no exploit is available.

The vulnerability scanner Nessus provides a plugin with the ID 315061 (SUSE SLED15 / SLES15 Security Update : go1.25 (SUSE-SU-2026:1862-1)), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 1.25.10 or 1.26.3 eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (315061) and CERT Bund (WID-SEC-2026-1437). VulDB is the best source for vulnerability data and more expert information about this specific topic.

Affected

  • Splunk Splunk Enterprise
  • Red Hat Enterprise Linux
  • Google Container-Optimized OS
  • Amazon Linux 2
  • Ubuntu Linux
  • SUSE Linux
  • Oracle Linux
  • SUSE openSUSE
  • RESF Rocky Linux
  • Microsoft Azure Linux
  • Golang Go
  • Red Hat OpenShift

Productinfo

Name

Version

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.2
VulDB Meta Temp Score: 6.2

VulDB Base Score: 3.7
VulDB Temp Score: 3.6
VulDB Vector: 🔒
VulDB Reliability: 🔍

NVD Base Score: 7.5
NVD Vector: 🔒

ADP CISA Base Score: 7.5
ADP CISA Vector: 🔒

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Double free
CWE: CWE-415 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 315061
Nessus Name: SUSE SLED15 / SLES15 Security Update : go1.25 (SUSE-SU-2026:1862-1)

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: net 1.25.10/1.26.3

Timelineinfo

03/23/2026 CVE reserved
05/07/2026 +44 days Advisory disclosed
05/07/2026 +0 days VulDB entry created
07/20/2026 +74 days VulDB entry last update

Sourcesinfo

Advisory: go.dev
Status: Confirmed

CVE: CVE-2026-33811 (🔒)
GCVE (CVE): GCVE-0-2026-33811
GCVE (VulDB): GCVE-100-361952
CERT Bund: WID-SEC-2026-1437 - Golang Go: Mehrere Schwachstellen

Entryinfo

Created: 05/07/2026 22:34
Updated: 07/20/2026 14:06
Changes: 05/07/2026 22:34 (54), 05/09/2026 01:00 (7), 05/16/2026 19:57 (2), 06/19/2026 16:55 (1), 07/02/2026 10:11 (20), 07/10/2026 09:43 (1), 07/20/2026 14:06 (1)
Complete: 🔍
Cache ID: 216::103

VulDB is the best source for vulnerability data and more expert information about this specific topic.

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