VulnerabilityModified
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.
HIGH 7.5EPSS 0.81%
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.81%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 0.81% probability · 55th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-415, CWE-1341
- Affected
- golang/go
- Source
- security@golang.org
References
- https://go.dev/cl/767860Patch
- https://go.dev/issue/78803Issue Tracking
- https://groups.google.com/g/golang-announce/c/qcCIEXso47MMailing List, Third Party Advisory
- https://pkg.go.dev/vuln/GO-2026-4981Vendor 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
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.