The rpm-ostree tool, which integrates RPM packaging with OSTree bootable file system trees, had a security flaw where the /etc/shadow file was world-readable, potentially exposing sensitive password hash information. This vulnerability is tracked as CVE-2024-2905 and is rated moderate by Red Hat Product Security. The flaw affects Red Hat Enterprise Linux 9.4 Extended Update Support and related variants across multiple architectures including x86_64, s390x, ppc64le, and aarch64. Red Hat has issued a security advisory (RHSA-2024:3823) and released updated rpm-ostree packages to correct the file permission issue.

The vulnerability allows unauthorized users to read the /etc/shadow file, which contains hashed user passwords. Exposure of this file could facilitate offline password cracking attempts, potentially leading to privilege escalation or unauthorized access if weak passwords are used. However, the issue is rated moderate, indicating that while the exposure is serious, exploitation requires additional factors such as local access or other conditions.

Red Hat has released an official security update for rpm-ostree that corrects the file permission issue with /etc/shadow. Users of affected Red Hat Enterprise Linux 9.4 Extended Update Support versions should apply the update as soon as possible. For detailed update instructions, refer to Red Hat's advisory and knowledge base article at https://access.redhat.com/articles/11258. No additional mitigation is required beyond applying the official patch.