CVE-2025-53819

Root privilege escalation via unreachable build-user branch

Published Jul 14, 2025 · Updated Jul 15, 2025

Privilege dropping errors in Nix 2.30.0 allow local users on macOS to execute package builds with root privileges. In src/libstore/unix/user-lock.cc, useBuildUsers() joins the mutually exclusive APPLE and FreeBSD tests with &&, making the build-user branch unreachable. Any user permitted to submit builds to the multi-user Nix daemon can run build instructions as root, enabling privilege escalation and root-level file or command access.

CVSS severity7.9
High
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Privilege dropping errors in Nix 2.30.0 allow local users on macOS to execute package builds with root privileges. In src/libstore/unix/user-lock.cc, useBuildUsers() joins the mutually exclusive APPLE and FreeBSD tests with &&, making the build-user branch unreachable. Any user permitted to submit builds to the multi-user Nix daemon can run build instructions as root, enabling privilege escalation and root-level file or command access.

The record

CVE
CVE-2025-53819
Published
Jul 14, 2025
Updated
Jul 15, 2025
Vendor
NixOS
Product
Nix
Classifications
CWE-271, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 14, 2025CVE publishedPublication date reported by the CVE source.
  2. Jul 15, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion== 2.30.0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

NixOS · Nixversion== 2.30.0

Published CVSS scores

7.9GitHubCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:L/I:H/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-271Privilege Dropping / Lowering Errors
T1068Exploitation for Privilege Escalation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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