Double-free in Go net LookupCNAME with cgo DNS resolver
CVE-2026-33811 is a memory-management vulnerability in Go's net package affecting the cgo DNS resolver path used by LookupCNAME. When an application performs a LookupCNAME call through the cgo resolver, a very long CNAME response can trigger a double-free of C-allocated memory. The resulting memory corruption condition causes the affected Go process to crash. The issue is tracked by the Go project as issue 78803 and was fixed by the Go maintainers.
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Impact, mitigation & remediation
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Impact
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Mitigation
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Remediation
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Exploits
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No public exploit code observed for this vulnerability.
Affected products & vendors
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Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.
Recent activity
13 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.
The version that knows your environment.
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Every observed campaign linking this CVE to a named adversary.
Malware families riding this exploit, with evidence and IOCs.
YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.
Cross-references every affected SKU, including bundled OEM variants.
Community discussion across Reddit, Mastodon, and other social sources.