Cyber Resilience

CVE-2026-33811

Memory Safety in Golang Go ≤ 1.25.10

Memory Safety
Published
07 May 2026
Modified
29 July 2026
Patch / advisory
View advisory
CVSS Score v3.1 7.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS Score 0.0081 53th percentile
Risk Priority 55 floored blend · peak EPSS

Summary

CVE-2026-33811 is a high-severity Double Free (CWE-415) vulnerability in Golang Go. Its CVSS base score is 7.5 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Application or System Exploitation (T1499.004); ranked in the top 47% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

The strongest mitigations our analysis identified map to SI-10 (Information Input Validation) and SI-2 (Flaw Remediation) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

When using LookupCNAME with the cgo DNS resolver, a very long CNAME response can trigger a double-free of C memory and a crash.

CWE(s)
CWE-415CWE-1341

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1499.004 Application or System Exploitation Impact
Adversaries may exploit software vulnerabilities that can cause an application or system to crash and deny availability to users.
attack.mitre.org →
Why these techniques?

Double-free in DNS resolver triggered by crafted CNAME response directly enables endpoint DoS via application exploitation.

Confidence: HIGH · MITRE ATT&CK Enterprise v19.0

CVEs Like This One

CVE-2026-42499Same product: Golang Go
CVE-2026-32281Same product: Golang Go
CVE-2026-32283Same product: Golang Go
CVE-2026-39836Same product: Golang Go
CVE-2026-27137Same product: Golang Go
CVE-2026-25679Same product: Golang Go
CVE-2025-61728Same product: Golang Go
CVE-2026-27138Same product: Golang Go
CVE-2026-32288Same product: Golang Go
CVE-2026-32280Same product: Golang Go

Affected Assets

golang
go
≤ 1.25.10 · 1.26.0 — 1.26.3

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)
  • SI-2 Flaw Remediation
  • SI-10 Information Input Validation
  • SC-7 Boundary Protection
Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)
  • 1 hardening rule · 1 OS baseline
Validate
Prove the fix (OWASP ASVS)

—

Mitigating Controls (NIST 800-53 r5) AI

SI-2 Flaw Remediation good match
prevent

Directly requires applying patches or updates to eliminate the double-free flaw in the cgo DNS resolver triggered by long CNAME responses.

SI-10 Information Input Validation good match
prevent

Enforces validation of DNS response data (e.g., CNAME length and structure) before processing, blocking the malformed input that causes the double-free.

SC-7 Boundary Protection partial match
prevent

Boundary protection at the DNS resolver level can filter or sanitize external responses, limiting exposure to malicious long CNAME records from untrusted servers.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 full match
prevents

Secure SDLC practices directly prevent double-free errors via static analysis, safe memory APIs, and testing.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.8.29 Security testing in development and acceptance mostly match
detects

Security testing in development can detect double-free conditions before release.

A.8.25 Secure development life cycle partial match
prevents

Secure development life cycle includes memory-safety practices that can prevent double-free bugs.

A.8.26 Application security requirements partial match
prevents

Application security requirements can mandate memory-safety rules that reduce double-free risk.

A.8.27 Secure system architecture and engineering principles partial match
prevents

Secure system architecture and engineering principles can prescribe safe memory-management patterns.

A.8.28 Secure coding partial match
prevents

Secure coding standards directly address proper use of free() and similar functions.

References