CVE-2026-33811

HIGHNVD 7.57.5—

7.5

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

CVSS v3: 7.5
EG Score: 7.5(high)
EPSS: 4.4%
KEV: Not listed

Published

May 7, 2026

Last Modified

May 12, 2026

Advisory Details (4)

Auto-updated May 12, 2026

No patch confirmed yet.

generic

GO-2026-4981 - Go Packages

https://pkg.go.dev/vuln/GO-2026-4981

generic

https://groups.google.com/g/golang-announce/c/qcCIEXso47M

generic

net: double-free of cgo pointer when handling long CNAME response · Issue #78803 · golang/go · GitHub

https://go.dev/issue/78803

generic

https://go.dev/cl/767860

Vendor Advisories for CVE-2026-33811(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

CVE-2026-33811
Microsoft Security Response Center (MSRC)
Crash when handling long CNAME response in net

Frequently asked(5)

What is CVE-2026-33811?

CVE-2026-33811 is a high vulnerability published on May 7, 2026. When using LookupCNAME with the cgo DNS resolver, a very long CNAME response can trigger a double-free of C memory and a crash.

When was CVE-2026-33811 disclosed?

CVE-2026-33811 was first published in the National Vulnerability Database on May 7, 2026, with the most recent update on May 12, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2026-33811 actively exploited?

CVE-2026-33811 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 4.4% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2026-33811?

CVE-2026-33811 has a CVSS v3 base score of 7.5 (NVD).

How do I remediate CVE-2026-33811?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-33811, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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CVE-2026-33811

📅 Published

🔄 Last Modified

📋 Advisory Details (4)

GO-2026-4981 - Go Packages

net: double-free of cgo pointer when handling long CNAME response · Issue #78803 · golang/go · GitHub

📣 Vendor Advisories for CVE-2026-33811(1)

❓ Frequently asked(5)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2026-33811?

Published

Last Modified

Advisory Details (4)

Vendor Advisories for CVE-2026-33811(1)

Frequently asked(5)