No exploitation reportedFix available

CVE-2026-33811

Q: Is CVE-2026-33811 actively exploited?

Active exploitation of CVE-2026-33811 has not been confirmed. Its EPSS score was 0.8% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2026-33811?

CVE-2026-33811 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

Crash when handling long CNAME response in net

No exploitation reported by the sources we read.

Published2026-05-07
Fixed in1.26.3 · 1.25.10
WeaknessCWE-1341 · CWE-415

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC

2026-05-0720:16CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2026-33811?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2026-33811?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD · OSV

Branch	Affected	Fixed in	Source
1.26	≥ 1.26.0, < 1.26.3	1.26.3	NVD
1.25	< 1.25.10	1.25.10	NVD · OSV

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

aardvark-dnsAlmaLinux:8all versions · fixed in 2:1.10.1-2.module_el8.10.0+3901+4b80ecd7
buildahAlmaLinux:8all versions · fixed in 2:1.33.14-4.module_el8.10.0+4213+0493256band 1 other package
cockpit-podmanAlmaLinux:8all versions · fixed in 84.1-1.module_el8.10.0+4102+6c76e544
conmonAlmaLinux:8all versions · fixed in 3:2.1.10-1.module_el8.10.0+4068+0e21408f
container-selinuxAlmaLinux:8all versions · fixed in 2:2.229.0-3.module_el8.10.0+4213+0493256b
containernetworking-pluginsAlmaLinux:8all versions · fixed in 1:1.4.0-8.module_el8.10.0+4136+16425343
containers-commonAlmaLinux:8all versions · fixed in 2:1-82.module_el8.10.0+4089+ce72bbbe
critAlmaLinux:8all versions · fixed in 3.18-5.module_el8.10.0+3845+87b84552

27 more package ranges on OSV.dev

Vendor advisories

CVE-2026-33811 Red Hat Product Security1,962 products fixed · 137 known affected
net: golang: Go net package: Denial of Service via long CNAME response in LookupCNAME
rhai/assisted-installer-rhel9 as a component of Assisted Installer for Red Hat OpenShift Container Platform 2 · compliance/openshift-compliance-rhel8-operator as a component of Compliance Operator · build-of-trustee/trustee-rhel9-operator as a component of Confidential Compute Attestation · +134 more
RHSA-2026:87410 Red Hat Product Security5 products fixed
Red Hat Security Advisory: RHOAI 2.25.12 - Red Hat OpenShift AI
RHSA-2026:84734 Red Hat Product Security27 products fixed
Red Hat Security Advisory: RHOAI 3.4.5 - Red Hat OpenShift AI
RHSA-2026:82372 Red Hat Product Security4 products fixed
Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.18.2
RHSA-2026:82354 Red Hat Product Security4 products fixed
Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.18.2
RHSA-2026:82347 Red Hat Product Security8 products fixed
Red Hat Security Advisory: cert-manager Operator for Red Hat OpenShift 1.18.2

138 more advisories

Full record on NVD

Fix

Update Go to 1.26.3 · 1.25.10
Vendor fix Red Hat Product Security RHSA-2026:87410 · 5 productsFor Red Hat OpenShift AI 2.25.12 see the following documentation, which will be updated shortly for this release, for important instructions on how to upgrade your cluster and fully apply this errata update: https://docs.redhat.com/en/documentation/red_hat_openshift_ai/
Vendor fix Red Hat Product Security RHSA-2026:84734 · 27 productsFor Red Hat OpenShift AI 3.4.5 see the following documentation, which will be updated shortly for this release, for important instructions on how to upgrade your cluster and fully apply this errata update: https://docs.redhat.com/en/documentation/red_hat_openshift_ai/
Vendor fix Red Hat Product Security RHSA-2026:82372 · 4 productsBefore applying this update, make sure all previously released errata relevant to your system have been applied. The steps to apply the upgraded images are different depending on the installation plan approval policy you used when installing the cert-manager Operator for Red Hat OpenShift. - If t…
Vendor fix Red Hat Product Security RHSA-2026:80684 · 1 productThe container images provided by this update can be downloaded from the Red Hat container registry at registry.redhat.io or registry.access.redhat.com using the 'podman pull' command. For more information about the images, search the image name in the Red Hat Ecosystem Catalog.
Vendor fix Red Hat Product Security RHSA-2026:77532 · 1 productThe Service Telemetry Framework container image provided by this update can be downloaded from the Red Hat Container Registry at registry.access.redhat.com. Installation instructions for your platform are available at Red Hat Container Catalog (see References). Dockerfiles and scripts should be am…
Vendor fix Red Hat Product Security RHSA-2026:76752 · 2 productsBefore applying this update, make sure all previously released errata relevant to your system have been applied. For details on how to apply this update, refer to: https://docs.openshift.com/container-platform/latest/updating/updating_a_cluster/updating-cluster-cli.html

Advisories and patches

go.devPatch
pkg.go.devVendor Advisory

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

CISA-ADPSSVC decisionnone2026-05-08
OpenCVESSVC decisionnone—
CISA-ADPCVSS 3.17.52026-05-08
CNACVSS 3.17.5read 2026-10-23
NVDCVSS 3.17.5read 2026-10-23
CNAweakness (CWE)CWE-1341read 2026-10-23
NVDweakness (CWE)CWE-415read 2026-10-23
FIRST EPSSEPSS score0.8 %2026-10-22
OSVaffected packages—
Microsoft MSRCadvisory—

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published: 2026-05-07
Last Modified: 2026-09-18
NVD status: Modified
MSRC Title: Crash when handling long CNAME response in net

Frequently asked questions

What is 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 crash.

Is CVE-2026-33811 actively exploited?

Active exploitation of CVE-2026-33811 has not been confirmed. Its EPSS score was 0.8% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

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

CVE-2026-33811 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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