Ubuntu

A local privilege escalation vulnerability exists in snap-confine, a set-capabilities core component used internally by Canonical snapd to construct the secure execution environment for snap applications. This vulnerability uniquely affects versions of snap-confine configured with set-capabilities (rather than standard set-uid-root installations). Due to a flaw in how privilege boundaries or security sandboxes are initialized when the binary runs under limited ambient capabilities, a local, unprivileged attacker can exploit this behavior to bypass intended restrictions and execute arbitrary code. Successful exploitation allows the local user to elevate their privileges to full root authority.

A sandbox confinement bypass vulnerability exists in Canonical snapd within its internal execution environment compiler (snap-confine). The default seccomp security templates generated by the engine to restrict system calls do not filter or reject process operations capable of creating or manipulating file execution flags with set-user-ID attributes. Consequently, an application running within a strictly confined snap environment can successfully compile or drop binaries and apply setuid properties to them. If a compromised or malicious process inside the snap sandbox executes these generated setuid binaries, it can potentially circumvent architectural sandboxing assumptions, drop intended restriction policies, or execute privileged actions inside the container namespace that should otherwise be strictly blocked. The vulnerability has been resolved by hardening the seccomp template engine to block the execution and creation of setuid executables by sandboxed snap processes.

An input validation and injection vulnerability exists in Canonical ubuntu-pro-client (formerly ubuntu-advantage-tools). The client constructs APT source files (such as /etc/apt/sources.list.d/ubuntu-.list or their DEB822 equivalents) using data received directly from the contract server response via the directives.suites[] and directives.aptURL fields. Because the client utilizes Python's str.format() to write these files without performing escaping, validation, or newline character filtering, a malicious or tampered contract response containing embedded newline (\n) characters can successfully inject arbitrary, attacker-controlled deb configuration lines into root-owned APT sources. When combined with the unvalidated additionalPackages[] field—which is passed positionally into a root-executed apt-get install command—an attacker capable of spoofing or manipulating the contract response (e.g., via a compromised internal infrastructure, an intercepted connection utilizing a trusted CA, or local logical bugs) can force the client to fetch and install malicious packages. This ultimately leads to arbitrary code execution with root privileges on the affected system. This component is preinstalled on supported Ubuntu Server releases and auto-attaches by default on cloud provider Ubuntu Pro images.

A sandbox escape vulnerability exists in the OpenJDK packages provided in Ubuntu. The .jar MIME handlers installed by these packages execute files marked as executable when the mailcap package is installed. A compromised or malicious sandboxed application with access to the OpenURI portal via xdg-desktop-portal-gtk can write a malicious .jar file to the host file system, set its executable bit, and trigger the handler to execute arbitrary code outside of the sandbox environment.

An issue was discovered in Canonical ADSys upstream versions through v0.16.2. During Active Directory Certificate Services (AD CS) certificate auto-enrollment via the vendored Samba client script (internal/policies/certificate/python/vendor_samba/gp/gp_cert_auto_enroll_ext.py), ADSys utilizes a plaintext HTTP connection (http://) instead of a secure HTTPS connection (https://) to request the CA certificate from the Active Directory Certificate Services server (GetCACert). An unauthenticated network attacker positioned between the managed Ubuntu host and the configured AD CS CA hostname can conduct a Man-in-the-Middle (MITM) attack. By intercepting the plaintext HTTP request, the attacker can supply an arbitrary, attacker-controlled Root CA certificate. Because the system automatically accepts this certificate and registers it into the local system trust store via update-ca-certificates, this results in system-wide trust store poisoning. Consequently, TLS clients utilizing the operating system trust store on the affected machine will accept rogue certificates for arbitrary domains, enabling persistent decryption and interception of subsequent TLS connections. This issue is resolved in version v0.16.3.

Local privilege escalation in snapd on Linux allows local attackers to get root privilege by re-creating snap's private /tmp directory when systemd-tmpfiles is configured to automatically clean up this directory. This issue affects Ubuntu 16.04 LTS, 18.04 LTS, 20.04 LTS, 22.04 LTS, and 24.04 LTS.