CVE-2026-33811

HIGHNVD 7.57.5—Trending — 3 sources updated this week

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: 4.3%
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)High
Crash when handling long CNAME response in net

Affected Packages

(1 across 1 ecosystem)

Go(1)

Package	Vulnerable range	Fixed in	Dependents
stdlib	—	1.26.3	—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

CWE-415Double Free

Data Freshness Timeline

(refreshed 20× in last 7d / 20× in last 30d)

Every time one of our enrichment pipelines (NVD, MITRE cvelistV5, EPSS, CISA KEV, GHSA, OSV, vendor advisories) ran against this CVE. Most recent first.

2026-06-03 18:13 UTCEG score recompute
2026-06-03 18:13 UTCGHSA enrichment
2026-06-03 06:47 UTCEG score recompute
2026-06-03 06:47 UTCGHSA enrichment
2026-06-02 20:13 UTCepss_batch
2026-06-02 19:21 UTCEG score recompute
2026-06-02 19:21 UTCGHSA enrichment
2026-06-02 07:55 UTCEG score recompute
2026-06-02 07:55 UTCGHSA enrichment
2026-06-01 20:29 UTCEG score recompute
2026-06-01 20:29 UTCGHSA enrichment
2026-06-01 13:52 UTCepss_batch
2026-06-01 13:52 UTCepss_batch
2026-06-01 13:51 UTCepss_batch
2026-06-01 08:58 UTCEG score recompute
2026-06-01 08:58 UTCGHSA enrichment
2026-05-31 22:30 UTCepss_batch
2026-05-31 22:30 UTCepss_batch
2026-05-31 00:16 UTCepss_batch
2026-05-31 00:16 UTCepss_batch

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 4.3% 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.

Dependency Blast Radius

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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)

Affected Packages

Weakness Classification(1)

Data Freshness Timeline

❓ Frequently asked(5)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2026-33811?

🔗 Related CVEs(same CWE)

Same CWE

Published

Last Modified

Advisory Details (4)

Vendor Advisories for CVE-2026-33811(1)

Frequently asked(5)

Related CVEs(same CWE)