CVE-2026-33811: CWE-415: Double Free in Go standard library net
When using LookupCNAME with the cgo DNS resolver, a very long CNAME response can trigger a double-free of C memory and a crash.
AI Analysis
Technical Summary
The vulnerability CVE-2026-33811 involves a double-free memory error (CWE-415) triggered when the Go standard library's net package uses LookupCNAME with the cgo DNS resolver and encounters a very long CNAME DNS response. This double-free of C memory results in a crash of the application. The affected versions include Go standard library versions from 0 up to 1.26.0-0. No CVSS score or vendor advisory detailing a fix or mitigation is currently available.
Potential Impact
The impact is a denial of service condition caused by a crash due to double-free memory corruption when processing certain DNS responses. There is no information about code execution or data corruption beyond the crash. No known exploits have been reported in the wild.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is released, users should consider avoiding the use of LookupCNAME with the cgo DNS resolver on untrusted or potentially malicious DNS responses that could trigger this vulnerability.
CVE-2026-33811: CWE-415: Double Free in Go standard library net
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.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The vulnerability CVE-2026-33811 involves a double-free memory error (CWE-415) triggered when the Go standard library's net package uses LookupCNAME with the cgo DNS resolver and encounters a very long CNAME DNS response. This double-free of C memory results in a crash of the application. The affected versions include Go standard library versions from 0 up to 1.26.0-0. No CVSS score or vendor advisory detailing a fix or mitigation is currently available.
Potential Impact
The impact is a denial of service condition caused by a crash due to double-free memory corruption when processing certain DNS responses. There is no information about code execution or data corruption beyond the crash. No known exploits have been reported in the wild.
Mitigation Recommendations
Patch status is not yet confirmed — check the vendor advisory for current remediation guidance. Until an official fix is released, users should consider avoiding the use of LookupCNAME with the cgo DNS resolver on untrusted or potentially malicious DNS responses that could trigger this vulnerability.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- Go
- Date Reserved
- 2026-03-23T20:35:32.814Z
- Cvss Version
- null
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 69fcf0c1cbff5d86102bd5ac
Added to database: 5/7/2026, 8:06:25 PM
Last enriched: 5/7/2026, 8:22:26 PM
Last updated: 5/9/2026, 1:08:27 AM
Views: 15
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