Cyber Resilience

CVE-2026-39819

Golang Go ≤ 1.25.10

Published
07 May 2026
Modified
17 June 2026
Patch / advisory
View advisory
CVSS Score v3.1 5.3
Click a component to see what it means
Raw vectorCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:H/A:N
EPSS Score 0.0018 8th percentile
Risk Priority 35 floored blend · peak EPSS

Summary

CVE-2026-39819 is a medium-severity Link Following (CWE-59) vulnerability in Golang Go. Its CVSS base score is 5.3 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 8th percentile by exploit likelihood (below the median); 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.

OWASP Top 10 for Web (2025)

A01:2025 Broken Access Control

EU & UK References

Vulnerability Data

The "go bug" command writes to two files with predictable names in the system temporary directory (for example, "/tmp"). An attacker with access to the temporary directory can create a symlink in one of these names, causing "go bug" to…

more

overwrite the target of the symlink.

CWE(s)
CWE-59

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
attack.mitre.org →
Why these techniques?

Symlink attack on predictable temp files enables arbitrary overwrite, facilitating local privilege escalation via targeted file replacement.

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

CVEs Like This One

CVE-2026-32282Same product: Golang Go
CVE-2026-27144Same product: Golang Go
CVE-2026-27143Same product: Golang Go
CVE-2026-27139Same product: Golang Go
CVE-2025-47906Same product: Golang Go
CVE-2026-27142Same product: Golang Go
CVE-2026-39825Same product: Golang Go
CVE-2023-24537Same product: Golang Go
CVE-2023-24532Same product: Golang Go
CVE-2026-33810Same 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
  • AC-6 Least Privilege
Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)

—

Validate
Prove the fix (OWASP ASVS)
  • V15.4.2

Mitigating Controls (NIST 800-53 r5) AI

SI-2 Flaw Remediation good match
prevent

Directly addresses the flaw by requiring patching of the Go toolchain to eliminate predictable temporary file names used by 'go bug'.

SI-10 Information Input Validation good match
prevent

Requires validation of file paths and use of secure temporary-file primitives that do not follow untrusted symlinks.

AC-6 Least Privilege partial match
prevent

Limits the scope of damage an attacker can cause by ensuring the 'go bug' process runs with only the privileges needed to write its intended reports.

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 require code to validate paths and avoid unsafe link following.

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 can detect link-following flaws before release.

A.8.25 Secure development life cycle partial match
prevents

Secure SDLC practices can mandate link-resolution checks and canonicalization before file access.

A.8.26 Application security requirements partial match
prevents

Application security requirements can explicitly require safe handling of symbolic links and path traversal.

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

Secure architecture principles include input validation and safe file-access design patterns.

A.8.28 Secure coding partial match
prevents

Secure coding standards directly address canonicalization and symlink attacks during implementation.

A.8.3 Information access restriction none match
none

Access-control rules can limit which files are reachable, reducing exposure to malicious links.

References