Nixos Nix

Ubuntu 25.05: captive-browse CAP_NET_RAW privilege escalation
CVE-2026-25740 - February 09, 2026

captive browser, a dedicated Chrome instance to log into captive portals without messing with DNS settings. In 25.05 and earlier, when programs.captive-browser is enabled, any user of the system can run arbitrary commands with the CAP_NET_RAW capability (binding to privileged ports, spoofing localhost traffic from privileged services...). This vulnerability is fixed in 25.11 and 26.05.

Execution with Unnecessary Privileges

NixOS Odoo DB Manager Unauthenticated Access (v<25.11, <26.05)
CVE-2026-25137 9.1 - Critical - February 02, 2026

The NixOs Odoo package is an open source ERP and CRM system. From 21.11 to before 25.11 and 26.05, every NixOS based Odoo setup publicly exposes the database manager without any authentication. This allows unauthorized actors to delete and download the entire database, including Odoos file store. Unauthorized access is evident from http requests. If kept, searching access logs and/or Odoos log for requests to /web/database can give indicators, if this has been actively exploited. The database manager is a featured intended for development and not meant to be publicly reachable. On other setups, a master password acts as 2nd line of defence. However, due to the nature of NixOS, Odoo is not able to modify its own configuration file and thus unable to persist the auto-generated password. This also applies when manually setting a master password in the web-UI. This means, the password is lost when restarting Odoo. When no password is set, the user is prompted to set one directly via the database manager. This requires no authentication or action by any authorized user or the system administrator. Thus, the database is effectively world readable by anyone able to reach Odoo. This vulnerability is fixed in 25.11 and 26.05.

Files or Directories Accessible to External Parties

Tandoor Recipes DB File Exposure via Default MEDIA_ROOT (v23.0526.05)
CVE-2026-23838 - January 19, 2026

Tandoor Recipes is a recipe manager than can be installed with the Nix package manager. Starting in version 23.05 and prior to version 26.05, when using the default configuration of Tandoor Recipes, specifically using SQLite and default `MEDIA_ROOT`, the full database file may be externally accessible, potentially on the Internet. The root cause is that the NixOS module configures the working directory of Tandoor Recipes, as well as the value of `MEDIA_ROOT`, to be `/var/lib/tandoor-recipes`. This causes Tandoor Recipes to create its `db.sqlite3` database file in the same directory as `MEDIA_ROOT` causing it to be accessible without authentication through HTTP like any other media file. This is the case when using `GUNICORN_MEDIA=1` or when using a web server like nginx to serve media files. NixOS 26.05 changes the default value of `MEDIA_ROOT` to a sub folder of the data directory. This only applies to configurations with `system.stateVersion` >= 26.05. For older configurations, one of the workarounds should be applied instead. NixOS 25.11 has received a backport of this patch, though it doesn't fix this vulnerability without user intervention. A recommended workaround is to move `MEDIA_ROOT` into a subdirectory. Non-recommended workarounds include switching to PostgreSQL or disallowing access to `db.sqlite3`.

Insertion of Sensitive Information into Externally-Accessible File or Directory

Nix 2.30.0 Builds Run as Root Vulnerability (CVE-2025-53819)
CVE-2025-53819 - July 14, 2025

Nix is a package manager for Linux and other Unix systems. Builds with Nix 2.30.0 on macOS were executed with elevated privileges (root), instead of the build users. The fix was applied to Nix 2.30.1. No known workarounds are available.

Privilege Dropping / Lowering Errors

Race Condition in Nix, Lix, Guix PMs Allows UID/GID Escalation Pre-2.29.1
CVE-2025-52993 - June 27, 2025

A race condition in the Nix, Lix, and Guix package managers enables changing the ownership of arbitrary files to the UID and GID of the build user (e.g., nixbld* or guixbuild*). This affects Nix before 2.24.15, 2.26.4, 2.28.4, and 2.29.1; Lix before 2.91.2, 2.92.2, and 2.93.1; and Guix before 1.4.0-38.0e79d5b.

Race Condition

Nix/Lix/Guix: World-Readable Build Directory prior to 2.24.15
CVE-2025-52991 - June 27, 2025

The Nix, Lix, and Guix package managers default to using temporary build directories in a world-readable and world-writable location. This allows standard users to deceive the package manager into using directories with pre-existing content, potentially leading to unauthorized actions or data manipulation. This affects Nix before 2.24.15, 2.26.4, 2.28.4, and 2.29.1; Lix before 2.91.2, 2.92.2, and 2.93.1; and Guix before 1.4.0-38.0e79d5b.

Incorrect Default Permissions

Privilege Escalation via Build Isolation Bypass in Nix, Lix, Guix <2.4/1.4
CVE-2025-46416 - June 27, 2025

The Nix, Lix, and Guix package managers allow a bypass of build isolation in which a user can elevate their privileges to the build user account (e.g., nixbld or guixbuild). This affects Nix through 2.24.15, 2.26.4, 2.28.4, and 2.29.1; Lix through 2.91.2, 2.92.2, and 2.93.1; and Guix before 1.4.0-38.0e79d5b.

Improper Ownership Management

Race Condition in Nix/Lix/Guix allows arbitrary folder delete (CVE-2025-46415)
CVE-2025-46415 - June 27, 2025

A race condition in the Nix, Lix, and Guix package managers allows the removal of content from arbitrary folders. This affects Nix before 2.24.15, 2.26.4, 2.28.4, and 2.29.1; Lix before 2.91.2, 2.92.2, and 2.93.1; and Guix before 1.4.0-38.0e79d5b.

TOCTTOU

Nix 1.11-2.18.7: fetchurl TLS Cert Bypass (MITM Leakage)
CVE-2024-47174 - September 26, 2024

Nix is a package manager for Linux and other Unix systems. Starting in version 1.11 and prior to versions 2.18.8 and 2.24.8, `<nix/fetchurl.nix>` did not verify TLS certificates on HTTPS connections. This could lead to connection details such as full URLs or credentials leaking in case of a man-in-the-middle (MITM) attack. `<nix/fetchurl.nix>` is also known as the builtin derivation builder `builtin:fetchurl`. It's not to be confused with the evaluation-time function `builtins.fetchurl`, which was not affected by this issue. A user may be affected by the risk of leaking credentials if they have a `netrc` file for authentication, or rely on derivations with `impureEnvVars` set to use credentials from the environment. In addition, the commonplace trust-on-first-use (TOFU) technique of updating dependencies by specifying an invalid hash and obtaining it from a remote store was also vulnerable to a MITM injecting arbitrary store objects. This also applied to the impure derivations experimental feature. Note that this may also happen when using Nixpkgs fetchers to obtain new hashes when not using the fake hash method, although that mechanism is not implemented in Nix itself but rather in Nixpkgs using a fixed-output derivation. The behavior was introduced in version 1.11 to make it consistent with the Nixpkgs `pkgs.fetchurl` and to make `<nix/fetchurl.nix>` work in the derivation builder sandbox, which back then did not have access to the CA bundles by default. Nowadays, CA bundles are bind-mounted on Linux. This issue has been fixed in Nix 2.18.8 and 2.24.8. As a workaround, implement (authenticated) fetching with `pkgs.fetchurl` from Nixpkgs, using `impureEnvVars` and `curlOpts` as needed.

authentification

Nix 2.24 NAR Unpack Write-After-Open to Arbitrary Paths
CVE-2024-45593 8.8 - High - September 10, 2024

Nix is a package manager for Linux and other Unix systems. A bug in Nix 2.24 prior to 2.24.6 allows a substituter or malicious user to craft a NAR that, when unpacked by Nix, causes Nix to write to arbitrary file system locations to which the Nix process has access. This will be with root permissions when using the Nix daemon. This issue is fixed in Nix 2.24.6.

Directory traversal

Nix Build Process Local PrivEsc via Setuid Binary (before 2.23.1)
CVE-2024-38531 - June 28, 2024

Nix is a package manager for Linux and other Unix systems that makes package management reliable and reproducible. A build process has access to and can change the permissions of the build directory. After creating a setuid binary in a globally accessible location, a malicious local user can assume the permissions of a Nix daemon worker and hijack all future builds. This issue was patched in version(s) 2.23.1, 2.22.2, 2.21.3, 2.20.7, 2.19.5 and 2.18.4.

Nix 2.22.1 - Hash Cache Mismatch Allows Source Code Swap via PR
CVE-2024-36050 - May 18, 2024

Nix through 2.22.1 mishandles certain usage of hash caches, which makes it easier for attackers to replace current source code with attacker-controlled source code by luring a maintainer into accepting a malicious pull request.

Nix (versions <2.3.18, 2.18.2, 2.19.4, 2.20.5) FD Leak via Sockets
CVE-2024-27297 5.9 - Medium - March 11, 2024

Nix is a package manager for Linux and other Unix systems. A fixed-output derivations on Linux can send file descriptors to files in the Nix store to another program running on the host (or another fixed-output derivation) via Unix domain sockets in the abstract namespace. This allows to modify the output of the derivation, after Nix has registered the path as "valid" and immutable in the Nix database. In particular, this allows the output of fixed-output derivations to be modified from their expected content. This issue has been addressed in versions 2.3.18 2.18.2 2.19.4 and 2.20.5. Users are advised to upgrade. There are no known workarounds for this vulnerability.

TOCTTOU

Nix through 2.3 allows local users to gain access to an arbitrary user's account
CVE-2019-17365 - October 09, 2019

Nix through 2.3 allows local users to gain access to an arbitrary user's account because the parent directory of the user-profile directories is world writable.