Most recent entries from all

EUVD-2026-21651

fkie_cve-2021-20319

An improper signature verification vulnerability was found in coreos-installer. A specially crafted gzip installation image can bypass the image signature verification and as a consequence can lead to the installation of unsigned content. An attacker able to modify the original installation image can write arbitrary data, and achieve full access to the node being installed.

GHSA-3r3g-g73x-g593 — coreos-installer improperly verifies GPG signature when decompressing gzipped artifact

Affected: crates.io: coreos-installer

### Impact

coreos-installer fails to correctly verify GPG signatures when decompressing gzip-compressed artifacts. This allows bypass of signature verification in cases where coreos-installer decompresses a downloaded OS image, allowing an attacker who can modify the OS image to compromise a newly-installed system.

Default installations from ISO or PXE media in Fedora CoreOS, RHEL CoreOS, and RHEL for Edge are **not** affected, as coreos-installer installs from an OS image shipped as part of the install media.

These flows are affected:

1. Installing with `--image-file`, `--image-url`, or `coreos.inst.image_url`. For example, if a user has a local mirror of installation images, an attacker could replace an image with a gzip-compressed alternative (even if the file extension is `.xz`). The result:

``` $ coreos-installer install --image-url http://localhost:8080/image.xz /dev/loop0 Downloading image from http://localhost:8080/image.xz Downloading signature from http://localhost:8080/image.xz.sig > Read disk 749.9 MiB/749.9 MiB (100%) gpg: Signature made Mon 20 Sep 2021 02:41:50 PM EDT gpg: using RSA key 8C5BA6990BDB26E19F2A1A801161AE6945719A39 gpg: BAD signature from "Fedora (34) <fedora-34-primary@fedoraproject.org>" [ultimate] Install complete. ```

Notice that GPG reports a bad signature, but coreos-installer continues anyway. Automation that relies on coreos-installer's exit status will not notice either.

2. `coreos-ins…

gsd-2021-20319

RHSA-2021:3926 — Red Hat Security Advisory: OpenShift Container Platform 4.8.17 security and bug fix update

coreos-installer: incorrect signature verification on gzip-compressed install images

RUSTSEC-2022-0103 — Incorrect signature verification on gzip-compressed install images

Affected: crates.io: coreos-installer

The coreos-installer is a program to fetch a disk image and stream it to a target disk.

During the installation process the installation image gpg signatures are verified.

The signature verification can be bypassed for gzip-compressed images due to a flaw in gzip coreos-installer wrapper.

When the decoder encounters the gzip trailer, it signals EOF to its output and does not continue reading from its input. As a result, earlier wrappers don't notice that they've reached EOF.

In particular, the GPG wrapper does not check the exit code of GPG.

Thus, if an attacker can substitute an attacker-controlled gzipped disk image, installation will complete successfully without a valid signature.

This vulnerability impacts only specific, User-Provisioned Infrastructure (UPI) installation methods where coreos-installer is used and where gzip-compressed images are configured as the installation source.

The Installer-Provisioned Infrastructure (IPI) bare-metal installs do use coreos-installer, but this installation method uses an install image embedded in the live OS image (ISO or PXE image), therefore is not affected by this vulnerability.

This vulnerability is specific to some upstream Fedora CoreOS installation flows.