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Vulnerability record · CVE-2026-33811 · published 7 May 2026

CVE-2026-33811: Golang go double free vulnerability

Golang · Go

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

7.5 CVSS 3.1 High EPSS 0.88% · top 42.6% CWE-415 · Double freeCWE-1341 · CWE-1341
7.5CVSS 3.1 base score
0.88%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
132References
18 Sep 2026Last modified by NVD

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.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://go.dev/cl/767860 Patch
https://go.dev/issue/78803 Issue Tracking
https://groups.google.com/g/golang-announce/c/qcCIEXso47M Mailing ListThird Party Advisory
https://pkg.go.dev/vuln/GO-2026-4981 Vendor Advisory
https://access.redhat.com/errata/RHSA-2026:22112
https://access.redhat.com/errata/RHSA-2026:22120
https://access.redhat.com/errata/RHSA-2026:22121
https://access.redhat.com/errata/RHSA-2026:23262
https://access.redhat.com/errata/RHSA-2026:23264
https://access.redhat.com/errata/RHSA-2026:33120
https://access.redhat.com/errata/RHSA-2026:33123
https://access.redhat.com/errata/RHSA-2026:33142
https://access.redhat.com/errata/RHSA-2026:33150
https://access.redhat.com/errata/RHSA-2026:33574
https://access.redhat.com/errata/RHSA-2026:34357
https://access.redhat.com/errata/RHSA-2026:34359
https://access.redhat.com/errata/RHSA-2026:34364
https://access.redhat.com/errata/RHSA-2026:35832
https://access.redhat.com/errata/RHSA-2026:35993
https://access.redhat.com/errata/RHSA-2026:35994
https://access.redhat.com/errata/RHSA-2026:35995
https://access.redhat.com/errata/RHSA-2026:36207
https://access.redhat.com/errata/RHSA-2026:36319
https://access.redhat.com/errata/RHSA-2026:36617
https://access.redhat.com/errata/RHSA-2026:36625
https://access.redhat.com/errata/RHSA-2026:36648
https://access.redhat.com/errata/RHSA-2026:36651
https://access.redhat.com/errata/RHSA-2026:36776
https://access.redhat.com/errata/RHSA-2026:36796
https://access.redhat.com/errata/RHSA-2026:36797
https://access.redhat.com/errata/RHSA-2026:38504
https://access.redhat.com/errata/RHSA-2026:39266
https://access.redhat.com/errata/RHSA-2026:39272
https://access.redhat.com/errata/RHSA-2026:39319
https://access.redhat.com/errata/RHSA-2026:39573
https://access.redhat.com/errata/RHSA-2026:39810
https://access.redhat.com/errata/RHSA-2026:40118
https://access.redhat.com/errata/RHSA-2026:40945
https://access.redhat.com/errata/RHSA-2026:41019
https://access.redhat.com/errata/RHSA-2026:41030

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2026-33811), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.