Cyber Resilience

CVE-2026-27140

Access Control in Golang Go ≤ 1.25.9

Published
08 April 2026
Modified
25 July 2026
Patch / advisory
CVSS Score v3.1 8.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
EPSS Score 0.0066 48th percentile
Risk Priority 65 floored blend · peak EPSS

Summary

CVE-2026-27140 is a high-severity Incorrect Authorization (CWE-863) vulnerability in Golang Go. Its CVSS base score is 8.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 48th 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 AC-24 (Access Control Decisions) and AC-25 (Reference Monitor) — see the control section below for these in your framework.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2026-27140 affects the Go programming language's build process, specifically when using cgo with SWIG-generated files. The vulnerability arises from SWIG file names containing 'cgo' combined with well-crafted payloads, which bypass a trust layer (CWE-863: Incorrect Authorization). This enables code smuggling and arbitrary code execution at build time. It was published on 2026-04-08 with a CVSS v3.1 base score of 8.8 (AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H).

Attackers can exploit this vulnerability remotely with low complexity and no required privileges, but it relies on user interaction, such as a developer building a project from an untrusted source containing malicious SWIG files. Successful exploitation grants arbitrary code execution on the build machine, potentially compromising the entire development environment with high impacts on confidentiality, integrity, and availability.

Mitigation guidance is provided in the Go security advisory GO-2026-4871 (https://pkg.go.dev/vuln/GO-2026-4871), the golang-announce mailing list post (https://groups.google.com/g/golang-announce/c/0uYbvbPZRWU), the associated issue tracker (https://go.dev/issue/78335), and the code change list (https://go.dev/cl/763768).

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

SWIG file names containing 'cgo' and well-crafted payloads could lead to code smuggling and arbitrary code execution at build time due to trust layer bypass.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
T1548 Abuse Elevation Control Mechanism Privilege Escalation
Adversaries may circumvent mechanisms designed to control privilege elevation to gain higher-level permissions.
T1548.002 Bypass User Account Control Privilege Escalation
Adversaries may bypass UAC mechanisms to elevate process privileges on system.
T1548.003 Sudo and Sudo Caching Privilege Escalation
Adversaries may perform sudo caching and/or use the sudoers file to elevate privileges.
T1005 Data from Local System Collection
Adversaries may search local system sources, such as file systems, configuration files, local databases, virtual machine files, or process memory, to find files of interest and sensitive data prior to Exfiltration.
T1083 File and Directory Discovery Discovery
Adversaries may enumerate files and directories or may search in specific locations of a host or network share for certain information within a file system.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2025-4674Same product: Golang Go
CVE-2023-24537Same product: Golang Go
CVE-2023-24532Same product: Golang Go
CVE-2026-27144Same product: Golang Go
CVE-2025-68119Same product: Golang Go
CVE-2026-39817Same product: Golang Go
CVE-2025-22873Same product: Golang Go
CVE-2026-25679Same product: Golang Go
CVE-2023-24540Same product: Golang Go
CVE-2026-33811Same product: Golang Go

Affected Assets

golang
go
≤ 1.25.9 · 1.26.0 — 1.26.2

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)
  • 5 hardening rules · 3 OS baselines
Validate
Prove the fix (OWASP ASVS)

Mitigating Controls (NIST 800-53 r5) AI

AC-3 directly requires correct enforcement of authorization decisions on every access request, structurally preventing incorrect checks.

AC-24 ensures access-control decisions are made and applied consistently, reducing the chance of an incorrect authorization result.

A reference monitor that is always invoked and tamper-proof forces every authorization decision through a verified, correct path.

SI-10 requires validation of inputs used to construct resource names, directly stopping malformed or dangerous names from being accepted.

Least-privilege assignments shrink the set of authorizations that must be checked correctly, limiting exposure to flawed checks.

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.AA-05 mostly match
prevents

Defining, enforcing, and reviewing access authorizations and least privilege directly prevents incorrect authorization checks.

PR.PS-06 mostly match
prevents

Secure SDLC practices directly require input validation and sanitization to restrict resource names derived from untrusted data.

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.

finds

Security testing can detect improper filename handling but does not itself prevent the weakness.

prevents

Requiring consistency between access rights and classification plus formal approval steps ensures that the authorization logic correctly distinguishes between entities that should and should not be granted access.

prevents

Enforcing policy-driven approval and role-change reviews stops incorrect or stale authorization decisions from remaining in effect after job changes or terminations.

prevents

Secure development life cycle mandates input validation and safe resource naming practices that directly prevent CWE-641.

prevents

Application security requirements include rules for handling untrusted input when constructing file or resource names.

prevents

Secure system architecture principles discourage unsafe resource naming but do not prescribe specific controls.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

Oracle Linux 8 (2 rules)
  • V-248581 OL 8 must require users to provide a password for privilege escalation. prevents CWE-863
  • V-252656 The OL 8 operating system must not be configured to bypass password requirements for privilege escalation. prevents CWE-863
RHEL 7 (1 rule)
  • V-204430 The Red Hat Enterprise Linux operating system must be configured so that users must re-authenticate for privilege escalation. prevents CWE-863
RHEL 8 (1 rule)
  • V-251712 The RHEL 8 operating system must not be configured to bypass password requirements for privilege escalation. prevents CWE-863

References