There are 5 open security issues in bookworm.
1 important issue:
- 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.
4 issues left for the package maintainer to handle:
- CVE-2024-27297:
(needs triaging)
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.
- CVE-2024-36050:
(postponed; to be fixed through a stable update)
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.
- CVE-2024-38531:
(needs triaging)
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.
- CVE-2024-47174:
(needs triaging)
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.
You can find information about how to handle these issues in the security team's documentation.
![[bug history graph]](https://qa.debian.org/data/bts/graphs/n/nix.png){kind=link}