Cyber Resilience

CVE-2026-39817

Memory Safety in Golang Go ≤ 1.25.10

Published
07 May 2026
Modified
17 June 2026
Patch / advisory
CVSS Score v3.1 5.9
Click a component to see what it means
Raw vectorCVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:C/C:N/I:H/A:N
EPSS Score 0.0017 7th percentile
Risk Priority 35 floored blend · peak EPSS

Summary

CVE-2026-39817 is a medium-severity Out-of-bounds Write (CWE-787) vulnerability in Golang Go. Its CVSS base score is 5.9 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Ingress Tool Transfer (T1105); ranked at the 7th 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 AC-6 (Least Privilege) — see the control section below for these in your framework.

EU & UK References

Vulnerability Data

The "go tool pack" subcommand (usually used only by the compiler as an internal tool with known-good inputs) does not sanitize output filenames. Extracting a malicious archive file with the "pack" subcommand can write files to arbitrary locations on the…

more

filesystem.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1105 Ingress Tool Transfer Command And Control
Adversaries may transfer tools or other files from an external system into a compromised environment.
T1547.001 Registry Run Keys / Startup Folder Persistence
Adversaries may achieve persistence by adding a program to a startup folder or referencing it with a Registry run key.
T1554 Compromise Host Software Binary Persistence
Adversaries may modify host software binaries to establish persistent access to systems.
Why these techniques?

Arbitrary file write via unsanitized archive extraction directly enables dropping payloads (T1105), placing autostart scripts/binaries (T1547.001), and overwriting host binaries (T1554).

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

CVEs Like This One

CVE-2024-30307Shared CWE-787
CVE-2023-6228Shared CWE-787
CVE-2023-31470Shared CWE-787
CVE-2025-2288Shared CWE-787
CVE-2023-30653Shared CWE-787
CVE-2024-43825Shared CWE-787
CVE-2023-46542Shared CWE-787
CVE-2023-43866Shared CWE-787
CVE-2023-20775Shared CWE-787
CVE-2023-50965Shared CWE-787

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
  • AC-6 Least Privilege
  • CM-7 Least Functionality
Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)

Validate
Prove the fix (OWASP ASVS)

Mitigating Controls (NIST 800-53 r5) AI

prevent

Directly requires validation and sanitization of untrusted input such as archive filenames to block path traversal and arbitrary writes.

prevent

Running the pack subcommand under least-privilege accounts limits the scope of any successful arbitrary file write.

prevent

Disabling or restricting the pack subcommand (an internal compiler tool) reduces the attack surface for malicious archive extraction.

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-development practices (static analysis, bounds checking, code review) are the primary means of preventing out-of-bounds writes.

ID.RA-01 partial match
prevents

Vulnerability scanning and recording can discover out-of-bounds write flaws so they can be remediated.

PR.PS-02 partial match
prevents

Patching or replacing vulnerable software directly eliminates known instances of this coding weakness.

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.

detects

Security testing in development and acceptance can detect and prevent out-of-bounds write defects.

prevents

Secure development life cycle mandates practices that prevent out-of-bounds writes.

prevents

Application security requirements can specify bounds-checking and safe memory handling.

prevents

Secure architecture and engineering principles reduce the likelihood of buffer overflows.

prevents

Secure coding directly addresses out-of-bounds writes through language choice and coding standards.

prevents

Change management can enforce review gates that catch unsafe memory operations before deployment.

References