Sicherheitslücken in policykit-1

UBUNTU-CVE-2026-85498

[Regression in CVE-2026-4897 fix (polkit read_cookie()) - stack buffer underflow]

Polkit: polkit: denial of service via unbounded input processing through standard input

A flaw was found in polkit. A local user can exploit this by providing a specially crafted, excessively long input to the `polkit-agent-helper-1` setuid binary via standard input (stdin). This unbounded input can lead to an out-of-memory (OOM) condition, resulting in a Denial of Service (DoS) for the system.

Polkit: xml policy file with a large number of nested elements may lead to out-of-bounds write

A flaw was found in polkit. When processing an XML policy with 32 or more nested elements in depth, an out-of-bounds write can be triggered. This issue can lead to a crash or other unexpected behavior, and arbitrary code execution is not discarded. To exploit this flaw, a high-privilege account is needed as it's required to place the malicious policy file properly.

CVE-2021-4034

A local privilege escalation vulnerability was found on polkit's pkexec utility. The pkexec application is a setuid tool designed to allow unprivileged users to run commands as privileged users according predefined policies. The current version of pkexec doesn't handle the calling parameters count correctly and ends trying to execute environment variables as commands. An attacker can leverage this by crafting environment variables in such a way it'll induce pkexec to execute arbitrary code. When successfully executed the attack can cause a local privilege escalation given unprivileged users administrative rights on the target machine.

• Auf 0.105-14.1ubuntu0.5+esm1 aktualisieren

CVE-2016-2568

pkexec, when used with --user nonpriv, allows local users to escape to the parent session via a crafted TIOCSTI ioctl call, which pushes characters to the terminal's input buffer.