Crash when handling long CNAME response in net
Summary
| CVE | CVE-2026-33811 |
|---|---|
| State | PUBLISHED |
| Assigner | Go |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-05-07 20:16:42 UTC |
| Updated | 2026-07-10 12:16:41 UTC |
| 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. |
Risk And Classification
Primary CVSS: v3.1 7.5 HIGH from [email protected]
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS: 0.000180000 probability, percentile 0.047170000 (date 2026-05-12)
Problem Types: CWE-415 | CWE-1341 | CWE-415: Double Free | CWE-1341 Multiple Releases of Same Resource or Handle
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Primary | 7.5 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| 3.1 | ADP | DECLARED | 7.5 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| 3.1 | ADP | CVSS | 7.5 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| 3.1 | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | Secondary | 7.5 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| 3.1 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | Secondary | 7.5 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
CVSS v3.1 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD Known Affected Configurations (CPE 2.3)
Vendor Declared Affected Products
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| access.redhat.com/errata/RHSA-2026:34357 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:36797 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:23262 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:35832 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:36651 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:35993 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:35994 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| go.dev/issue/78803 | [email protected] | go.dev | Issue Tracking |
| access.redhat.com/errata/RHSA-2026:34364 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:36207 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:33123 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:36617 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:36319 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:35995 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| bugzilla.redhat.com/show_bug.cgi | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | bugzilla.redhat.com | |
| security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33811.json | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | security.access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:23264 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:36776 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| go.dev/cl/767860 | [email protected] | go.dev | Patch |
| pkg.go.dev/vuln/GO-2026-4981 | [email protected] | pkg.go.dev | Vendor Advisory |
| access.redhat.com/errata/RHSA-2026:33120 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| groups.google.com/g/golang-announce/c/qcCIEXso47M | [email protected] | groups.google.com | Mailing List, Third Party Advisory |
| access.redhat.com/errata/RHSA-2026:36625 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:36648 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:36796 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:33142 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:34359 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| access.redhat.com/security/cve/CVE-2026-33811 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:33150 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:33574 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: hamayanhamayan (en)
Additional Advisory Data
| Source | Time | Event |
|---|---|---|
| ADP | 2026-05-07T20:01:34.913Z | Reported to Red Hat. |
| ADP | 2026-05-07T19:41:19.285Z | Made public. |
Solutions
ADP: RHSA-2026:36796: RHEM 1.0 for RHEL 9
ADP: RHSA-2026:35832: Red Hat Enterprise Linux AppStream (v. 10)
ADP: RHSA-2026:34357: Red Hat Enterprise Linux AppStream (v. 10)
ADP: RHSA-2026:36776: Red Hat Enterprise Linux AppStream (v. 8)
ADP: RHSA-2026:36617: Red Hat Enterprise Linux AppStream (v. 9)
ADP: RHSA-2026:34359: Red Hat Enterprise Linux AppStream (v. 9)
ADP: RHSA-2026:34364: Logging Subsystem for Red Hat OpenShift 6.4
ADP: RHSA-2026:36625: Red Hat Advanced Cluster Security for Kubernetes 4.10
ADP: RHSA-2026:36207: Red Hat Advanced Cluster Security for Kubernetes 4.11
ADP: RHSA-2026:36319: Red Hat Advanced Cluster Security for Kubernetes 4.9
ADP: RHSA-2026:33574: Red Hat Developer Hub 1.9
ADP: RHSA-2026:36651: Red Hat Edge Manager 1.0
ADP: RHSA-2026:23262: Red Hat Hardened Images
ADP: RHSA-2026:23264: Red Hat Hardened Images
ADP: RHSA-2026:36648: Red Hat OpenShift Builds 1.7.4
ADP: RHSA-2026:35994: Red Hat OpenShift GitOps 1.19
ADP: RHSA-2026:35993: Red Hat OpenShift GitOps 1.20
ADP: RHSA-2026:35995: Red Hat OpenShift GitOps 1.21
ADP: RHSA-2026:33123: Red Hat OpenShift Service Mesh 3.1
ADP: RHSA-2026:33142: Red Hat OpenShift Service Mesh 3.2
ADP: RHSA-2026:33150: Red Hat OpenShift Service Mesh 3.3
ADP: RHSA-2026:33120: Red Hat OpenShift Service Mesh 3
ADP: RHSA-2026:36797: Red Hat Trusted Artifact Signer 1.4
Workarounds
ADP: To mitigate this issue, applications can be configured to use the pure Go DNS resolver instead of the `cgo` DNS resolver. This can be achieved by setting the `GODEBUG` environment variable to `netdns=go`. For example, to run a Go application with this mitigation: `GODEBUG=netdns=go /path/to/your/go/application`. This change may require restarting affected applications or services to take effect. Users should verify that this change does not negatively impact DNS resolution for their specific application environment.