Database/Kernel, userspace & hypervisor
polkit: out-of-bounds write parsing deeply nested XML policy files
Impact
polkit's XML policy parser writes out of bounds when a .policy file nests 32 or more elements. The result is at least a crash of the policy engine and, per Red Hat, arbitrary code execution is not ruled out. polkit is the authorisation broker behind systemd, NetworkManager and container tooling on every RHEL-family GPU node, so a crash there breaks privileged operations an operator relies on during maintenance. The saving grace is the precondition: an attacker already needs a high-privilege account to drop a policy file into a directory polkit reads, so this is a privilege-escalation-completion or persistence step rather than an initial foothold. Treat it as hardening on shared bastion and management hosts rather than a tenant-facing hole.
Who can reach it
Local, and requires an already high-privilege account - the attacker must be able to place a malicious .policy file in a polkit policy directory. No network or tenant-pod reachability.
What to do
Apply the distribution polkit update (Red Hat has errata for RHEL 6-10 and OpenShift Container Platform 4); upstream fix is polkit commit 107d3801361b9f9084f78710178e683391f1d245. polkitd is restarted by the package update, so this is a package upgrade plus daemon restart - no reboot and no node drain needed.
References
Related entries
- systemd-homed: local homed-managed user can gain membership in arbitrary system groupsCVE-2026-16742 · systemd-homed (homed-managed user record group membership)Medium
- systemd-machined: unvalidated RegisterMachine class lets a local user reach root command executionCVE-2026-4105 · systemd-machined (RegisterMachine D-Bus method, class parameter validation)Medium
- QEMU virtio-blk: malformed guest SCSI request causes host-heap out-of-bounds writeCVE-2026-48914 · QEMU virtio-blk device (SCSI request descriptor size validation)Medium
- Linux kernel (AF_UNIX): Use-after-free in unix_stream_sendpage - local privilege escalation, no capabilities neededCVE-2023-4622 · Linux kernel (AF_UNIX)Medium
- Linux kernel (net/sched ETS): Out-of-bounds indexing in the ETS qdisc - memory corruption from CAP_NET_ADMINCVE-2025-21692 · Linux kernel (net/sched ETS)Medium
- Linux kernel (drivers/bus/fsl-mc): The fsl-mc bus read its driver_override string without holding the device lock, soCVE-2026-53115 · Linux kernel (drivers/bus/fsl-mc)Medium
This entry is curated: imported from vendor advisories with machine assistance, not yet individually verified. Confirm against your vendor's advisory before acting, and report anything wrong.