CVE-2025-52991Public exploit

Build manipulation via attacker-controlled temporary directories

Published Jun 27, 2025 · Updated Jun 27, 2025

Incorrect default permissions in affected Nix releases allow local users to manipulate builds through precreated temporary directories. The daemon stages builds under predictable names in shared, world-readable and world-writable temporary locations, then trusts existing directory contents. A local user able to submit untrusted derivations can prepopulate those paths; the flaw causes integrity impact and contributes to root escalation only when chained with other issues.

CVSS severity3.2
Low
EPSS probability0.15%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect default permissions in affected Nix releases allow local users to manipulate builds through precreated temporary directories. The daemon stages builds under predictable names in shared, world-readable and world-writable temporary locations, then trusts existing directory contents. A local user able to submit untrusted derivations can prepopulate those paths; the flaw causes integrity impact and contributes to root escalation only when chained with other issues.

The record

CVE
CVE-2025-52991
Published
Jun 27, 2025
Updated
Jun 27, 2025
Vendor
NixOS
Product
Nix
Classifications
CWE-276, T1068
Attack vector
local
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 27, 2025CVE publishedPublication date reported by the CVE source.
  2. Jun 27, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=0 <2.24.15
  2. Affected versionversion=2.25.0 <2.26.4
  3. Affected versionversion=2.27.0 <2.28.4
  4. Affected versionversion=2.29.0 <2.29.1

What conditions does exploitation require?

Attack vectorlocal
Required privilegesunauthenticated

What is affected?

NixOS · Nixversion=0 <2.24.15; version=2.25.0 <2.26.4; version=2.27.0 <2.28.4; version=2.29.0 <2.29.1

Published CVSS scores

3.2NixOS CNACVSS:3.1/AV:L/AC:H/PR:N/UI:N/S:C/C:N/I:L/A:N

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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-276Incorrect Default Permissions
T1068Exploitation for Privilege Escalation

Public exploit references

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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