The Linux kernel before 3.4.5 on the x86 platform, when Physical Address Extension (PAE) is enabled, does not properly use the Page Middle Directory (PMD), which allows local users to cause a denial of service (panic) via a crafted application that triggers a race condition.
This is a vulnerability exploitable with only local access requires the attacker to have either
physical access to the vulnerable system or a local (shell) account. Examples of locally
exploitable vulnerabilities are peripheral attacks such as Firewire/USB DMA attacks, and
local privilege escalations (e.g., sudo).
Specialized access conditions exist. For example,
in most configurations, the attacking party must already have elevated privileges or spoof additional systems
in addition to the attacking system (e.g., DNS hijacking).
The attack depends on social engineering methods that would be easily detected by knowledgeable people.
For example, the victim must perform several suspicious or atypical actions.
The vulnerable configuration is seen very rarely in practice.
If a race condition exists, the window is very narrow.
Authentication is not required to access and exploit the vulnerability.
There is no impact to the confidentiality of the system.
There is no impact to the integrity of the system.
There is a total shutdown of the affected resource. The attacker can render the
resource completely unavailable.