CVE-2026-39860 Vulnerability Analysis & Exploit Details

CVE-2026-39860
Vulnerability Scoring

9.0
/10
Severe Risk

Cybersecurity professionals consider CVE-2026-39860 an immediate threat requiring urgent mitigation.

Attack Complexity Details

  • Attack Complexity: Low
    Exploits can be performed without significant complexity or special conditions.
  • Attack Vector: Local
    Vulnerability requires local system access.
  • Privileges Required: None
    No privileges are required for exploitation.
  • Scope: Changed
    Successful exploitation can impact components beyond the vulnerable component.
  • User Interaction: None
    No user interaction is necessary for exploitation.

CVE-2026-39860 Details

Status: Analyzed

Last updated: 🕓 15 Apr 2026, 16:12 UTC
Originally published on: 🕘 08 Apr 2026, 21:17 UTC

Time between publication and last update: 6 days

CVSS Release: version 3

CVSS3 Source

security-advisories@github.com

CVSS3 Type

Secondary

CVSS3 Vector

CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:N

CVE-2026-39860 Vulnerability Summary

CVE-2026-39860: Nix is a package manager for Linux and other Unix systems. A bug in the fix for CVE-2024-27297 allowed for arbitrary overwrites of files writable by the Nix process orchestrating the builds (typically the Nix daemon running as root in multi-user installations) by following symlinks during fixed-output derivation output registration. This affects sandboxed Linux builds - sandboxed macOS builds are unaffected. The location of the temporary output used for the output copy was located inside the build chroot. A symlink, pointing to an arbitrary location in the filesystem, could be created by the derivation builder at that path. During output registration, the Nix process (running in the host mount namespace) would follow that symlink and overwrite the destination with the derivation's output contents. In multi-user installations, this allows all users able to submit builds to the Nix daemon (allowed-users - defaulting to all users) to gain root privileges by modifying sensitive files. This vulnerability is fixed in 2.34.5, 2.33.4, 2.32.7, 2.31.4, 2.30.4, 2.29.3, and 2.28.6.

Assessing the Risk of CVE-2026-39860

Access Complexity Graph

The exploitability of CVE-2026-39860 depends on two key factors: attack complexity (the level of effort required to execute an exploit) and privileges required (the access level an attacker needs).

Exploitability Analysis for CVE-2026-39860

With low attack complexity and no required privileges, CVE-2026-39860 is an easy target for cybercriminals. Organizations should prioritize immediate mitigation measures to prevent unauthorized access and data breaches.

Understanding AC and PR

A lower complexity and fewer privilege requirements make exploitation easier. Security teams should evaluate these aspects to determine the urgency of mitigation strategies, such as patch management and access control policies.

Attack Complexity (AC) measures the difficulty in executing an exploit. A high AC means that specific conditions must be met, making an attack more challenging, while a low AC means the vulnerability can be exploited with minimal effort.

Privileges Required (PR) determine the level of system access necessary for an attack. Vulnerabilities requiring no privileges are more accessible to attackers, whereas high privilege requirements limit exploitation to authorized users with elevated access.

CVSS Score Breakdown Chart

Above is the CVSS Sub-score Breakdown for CVE-2026-39860, illustrating how Base, Impact, and Exploitability factors combine to form the overall severity rating. A higher sub-score typically indicates a more severe or easier-to-exploit vulnerability.

CIA Impact Analysis

Below is the Impact Analysis for CVE-2026-39860, showing how Confidentiality, Integrity, and Availability might be affected if the vulnerability is exploited. Higher values usually signal greater potential damage.

  • Confidentiality: High
    Exploiting CVE-2026-39860 can result in unauthorized access to sensitive data, severely compromising data privacy.
  • Integrity: High
    CVE-2026-39860 could allow unauthorized modifications to data, potentially affecting system reliability and trust.
  • Availability: None
    CVE-2026-39860 does not impact system availability.

CVE-2026-39860 References

External References

CWE Common Weakness Enumeration

CWE-61

CAPEC Common Attack Pattern Enumeration and Classification

  • Leveraging Race Conditions via Symbolic Links CAPEC-27 This attack leverages the use of symbolic links (Symlinks) in order to write to sensitive files. An attacker can create a Symlink link to a target file not otherwise accessible to them. When the privileged program tries to create a temporary file with the same name as the Symlink link, it will actually write to the target file pointed to by the attackers' Symlink link. If the attacker can insert malicious content in the temporary file they will be writing to the sensitive file by using the Symlink. The race occurs because the system checks if the temporary file exists, then creates the file. The attacker would typically create the Symlink during the interval between the check and the creation of the temporary file.

Vulnerable Configurations

  • cpe:2.3:a:nixos:nix:2.18.2:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.18.2:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.18.3:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.18.3:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.18.4:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.18.4:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.18.5:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.18.5:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.18.6:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.18.6:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.18.7:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.18.7:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.18.8:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.18.8:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.18.9:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.18.9:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.19.4:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.19.4:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.19.5:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.19.5:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.19.6:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.19.6:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.19.7:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.19.7:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.20.5:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.20.5:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.20.6:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.20.6:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.20.7:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.20.7:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.20.8:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.20.8:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.20.9:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.20.9:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.21.0:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.21.0:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.21.1:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.21.1:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.21.2:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.21.2:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.21.3:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.21.3:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.21.4:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.21.4:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.21.5:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.21.5:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.22.0:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.22.0:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.22.1:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.22.1:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.22.2:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.22.2:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.22.3:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.22.3:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.22.4:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.22.4:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.23.0:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.23.0:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.23.1:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.23.1:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.23.2:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.23.2:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.23.3:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.23.3:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.23.4:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.23.4:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.24.0:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.24.0:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.24.1:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.24.1:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.24.2:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.24.2:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.24.3:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.24.3:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.24.4:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.24.4:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.24.5:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.24.5:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.24.6:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.24.6:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.24.7:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.24.7:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.24.8:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.24.8:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.24.9:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.24.9:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.24.10:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.24.10:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.24.11:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.24.11:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.24.12:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.24.12:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.24.13:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.24.13:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.24.14:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.24.14:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.24.15:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.24.15:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.25.0:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.25.0:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.25.1:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.25.1:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.25.2:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.25.2:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.25.3:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.25.3:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.25.4:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.25.4:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.25.5:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.25.5:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.26.0:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.26.0:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.26.1:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.26.1:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.26.2:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.26.2:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.26.3:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.26.3:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.26.4:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.26.4:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.27.0:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.27.0:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.27.1:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.27.1:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.28.0:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.28.0:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.28.1:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.28.1:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.28.2:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.28.2:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.28.3:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.28.3:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.28.4:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.28.4:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.28.5:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.28.5:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.29.0:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.29.0:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.29.1:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.29.1:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.29.2:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.29.2:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.30.0:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.30.0:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.30.1:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.30.1:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.30.2:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.30.2:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.30.3:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.30.3:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.31.0:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.31.0:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.31.1:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.31.1:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.31.2:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.31.2:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.31.3:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.31.3:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.32.0:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.32.0:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.32.1:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.32.1:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.32.2:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.32.2:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.32.3:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.32.3:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.32.4:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.32.4:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.32.5:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.32.5:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.32.6:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.32.6:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.33.0:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.33.0:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.33.1:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.33.1:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.33.2:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.33.2:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.33.3:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.33.3:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.34.0:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.34.0:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.34.1:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.34.1:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.34.2:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.34.2:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.34.3:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.34.3:*:*:*:*:*:*:*
  • cpe:2.3:a:nixos:nix:2.34.4:*:*:*:*:*:*:*
    cpe:2.3:a:nixos:nix:2.34.4:*:*:*:*:*:*:*
  • cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*
    cpe:2.3:o:linux:linux_kernel:-:*:*:*:*:*:*:*

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