CVE-2011-3593

Vulnerability

The vulnerability resides in the vlan_hwaccel_do_receive function in net/8021q/vlan_core.c of the Linux kernel 2.6.32 as shipped with Red Hat Enterprise Linux 6. It was introduced by a Red Hat patch that incorrectly backported upstream changes. When the kernel receives a priority-tagged VLAN frame (VID=0), it triggers a panic, leading to a system crash [1][2].

Exploitation

An attacker needs only network access to send crafted VLAN frames with a priority tag (VID=0) to a vulnerable system. No authentication or user interaction is required. The attacker sends such frames, and upon processing, the kernel panics, causing an immediate denial of service [1].

Impact

Successful exploitation results in a denial of service (system crash), affecting the availability of the targeted system. There is no evidence of information disclosure, data corruption, or privilege escalation [1][2].

Mitigation

Red Hat addressed this issue in a kernel update for Red Hat Enterprise Linux 6. The fix was committed and released; users should apply the latest kernel updates from Red Hat. No workarounds are documented, and the vulnerability is not listed on the CISA Known Exploited Vulnerabilities (KEV) catalog [1][2].