Cyber Resilience

CVE-2026-42499

Golang Go ≤ 1.25.10

Published
07 May 2026
Modified
29 July 2026
Patch / 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 0.0080 53th percentile
Risk Priority 55 floored blend · peak EPSS

Summary

CVE-2026-42499 is a high-severity Creation of Immutable Text Using String Concatenation (CWE-1046) 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 SC-5 (Denial-of-service Protection) and SI-10 (Information Input Validation) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

Pathological inputs could cause DoS through consumePhrase when parsing an email address according to RFC 5322.

CWE(s)

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.
Why these techniques?

Vulnerability description directly describes DoS via exploitation of email address parsing (RFC 5322) with pathological inputs, mapping to application/system exploitation for endpoint DoS.

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

CVEs Like This One

CVE-2026-27138Same product: Golang Go
CVE-2026-32283Same product: Golang Go
CVE-2026-32281Same product: Golang Go
CVE-2026-39836Same product: Golang Go
CVE-2026-32288Same product: Golang Go
CVE-2026-27137Same product: Golang Go
CVE-2026-25679Same product: Golang Go
CVE-2025-61728Same product: Golang Go
CVE-2026-33811Same 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-10 Information Input Validation
  • SC-5 Denial-of-service Protection
Detect
Catch it (NIST detect / respond)
  • SI-4 System Monitoring
Harden
Shrink the surface (DISA STIG)

Validate
Prove the fix (OWASP ASVS)

Mitigating Controls (NIST 800-53 r5) AI

prevent

Directly enforces validation and sanitization of email address inputs to reject pathological RFC 5322 strings before consumePhrase parsing occurs.

prevent

Provides explicit denial-of-service protections that can throttle or drop inputs designed to trigger excessive resource consumption in address parsers.

detect

Enables monitoring and anomaly detection for sudden spikes in CPU or parsing latency caused by crafted email addresses.

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 mostly match
prevents

Secure SDLC practices directly enforce correct immutable string handling and catch concatenation anti-patterns at code time.

References