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

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

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

HIGH · CVSS 7.5 EPSS 0.00017
Schedule remediation
  • SSVC automatable: yes - attacks can be scripted at scale
  • CVSS base score ≥ 7.0
Sigma rules0 YARA rules0
⬡

Weakness Classification

CWE-415Double Free
▤

Affected Products & Versions

2
golang go< 1.25.10
golang go>= 1.26.0 and < 1.26.3
▤

Affected Packages

1
Language-ecosystem packages (from OSV) tied to this CVE, with the version that fixes it - the dependency-level detail NVD doesn’t carry.
Go stdlib fixed in 1.25.10, 1.26.3
▣

Scoring & Timeline

7.5
HIGH · CVSS v3.1 · security@golang.org
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD07 May 2026 · 08:16 PM
CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
SSVC triage · cisa-vulnrichment
Exploitation
none
Automatable
yes
Technical impact
partial
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
⚑

Vendor Advisories

7
suse-csafopenSUSE-SU-2026:20763-1
suse-csafopenSUSE-SU-2026:20762-1
suse-csafSUSE-SU-2026:1861-1
suse-csafSUSE-SU-2026:1862-1
msrcCVE-2026-33811
🔗

References & Sources

4
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://go.dev/cl/767860Patch
https://go.dev/issue/78803Issue Tracking
https://groups.google.com/g/golang-announce/c/qcCIEXso47MMailing ListThird Party Advisory
https://pkg.go.dev/vuln/GO-2026-4981Vendor Advisory
Intelligence Graph · click any node to traverse
CVETechnique ActorTool Family
drag to reposition · click any node to traverse · button top-right enlarges
External lookups - second-class, for what we don’t hold ourselves
NVDCVE.orgCISAVulnersExploit-DBGitHub PoCVulnCheck KEVGreyNoise
Vulnerabilities
CISA KEV catalog
CWE weaknesses
CAPEC attack patterns
Package vulnerabilities
Threat intelligence
Threat actors
Tools & malware
ATT&CK techniques
IOCs
Detection & defense
Sigma rules
YARA rules
Atomic Red Team tests
D3FEND countermeasures
Compliance
NIST 800-53
ISO 27001:2022
SOC 2 TSC
PCI-DSS v4.0
CIS Controls v8.1
About
All capabilities
Live statistics
Data sources
Privacy policy
Terms of service
threatengine.sh  ·  Open-source threat intelligence platform  ·  100+ authoritative sources  ·  Every fact traces to its origin