CVE-2024-5300 Missing authorization in Ubuntu 16.04 LTS
Malicious snaps can bypass sandbox restrictions to read system password hashes via systemd-userdbd if the service is installed.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2024-5300?
CVE-2024-5300 is a medium-severity missing authorization vulnerability in Canonical Ubuntu 16.04 LTS, published on 21 Jul 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
An access control bypass and information disclosure vulnerability exists in the base AppArmor security profile configuration of Canonical snapd. The abstraction rules located in /etc/apparmor.d/abstractions/nss-systemd (inherited via ) inadvertently permit strictly confined snap applications, which lack the privileged account-control interface, to interact directly with the io.systemd.Multiplexer and io.systemd.NameServiceSwitch UNIX domain sockets under /run/systemd/userdb/. On systems where the systemd-userdbd service is installed and operational, the service fails to distinguish between an unconfined root user on the host system and a restricted root user running within a snap application's sandbox (such as a daemon or configuration hook). Because systemd-userdbd returns "complete" user records—including sensitive hashed user passwords from /etc/shadow—when queried by a process running as root, a compromised or malicious strictly confined snap executing code as root can successfully query the Varlink interface to retrieve all system password hashes, bypassing intended snap sandbox restrictions. This issue is mitigated by the fact that systemd-userdbd is not installed by default on standard Ubuntu deployments.
Weakness: CWE-212
Which versions are affected by CVE-2024-5300?
Linux distribution packages (21)
systemd Red Hat:hummingbird:1 | All versions | 0:261-2.hum1 |
systemd-boot-unsigned Red Hat:hummingbird:1 | All versions | 0:261-2.hum1 |
systemd-container Red Hat:hummingbird:1 | All versions | 0:261-2.hum1 |
systemd-devel Red Hat:hummingbird:1 | All versions | 0:261-2.hum1 |
systemd-journal-remote Red Hat:hummingbird:1 | All versions | 0:261-2.hum1 |
systemd-libs Red Hat:hummingbird:1 | All versions | 0:261-2.hum1 |
systemd-networkd Red Hat:hummingbird:1 | All versions | 0:261-2.hum1 |
systemd-networkd-defaults Red Hat:hummingbird:1 | All versions | 0:261-2.hum1 |
systemd-oomd-defaults Red Hat:hummingbird:1 | All versions | 0:261-2.hum1 |
systemd-pam Red Hat:hummingbird:1 | All versions | 0:261-2.hum1 |
systemd-resolved Red Hat:hummingbird:1 | All versions | 0:261-2.hum1 |
systemd-rpm-macros Red Hat:hummingbird:1 | All versions | 0:261-2.hum1 |
systemd-shared Red Hat:hummingbird:1 | All versions | 0:261-2.hum1 |
systemd-standalone-repart Red Hat:hummingbird:1 | All versions | 0:261-2.hum1 |
systemd-standalone-shutdown Red Hat:hummingbird:1 | All versions | 0:261-2.hum1 |
systemd-standalone-sysusers Red Hat:hummingbird:1 | All versions | 0:261-2.hum1 |
systemd-standalone-tmpfiles Red Hat:hummingbird:1 | All versions | 0:261-2.hum1 |
systemd-sysusers Red Hat:hummingbird:1 | All versions | 0:261-2.hum1 |
systemd-tests Red Hat:hummingbird:1 | All versions | 0:261-2.hum1 |
systemd-udev Red Hat:hummingbird:1 | All versions | 0:261-2.hum1 |
systemd-ukify Red Hat:hummingbird:1 | All versions | 0:261-2.hum1 |
How do I fix CVE-2024-5300?
Apply the vendor's patch.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2024-5300 being exploited?
There is no known exploitation of CVE-2024-5300 in the wild and no public exploit code.
Sources
Also known as DEBIAN-CVE-2024-5300, GHSA-px3v-8ppp-543h, RHSA-2026:29009, UBUNTU-CVE-2024-5300.