|Date: (C)2007-09-17 (M)2017-10-04|
|CVSS Score: 4.9||Access Vector: LOCAL|
|Exploitability Subscore: 3.9||Access Complexity: LOW|
|Impact Subscore: 6.9||Authentication: NONE|
| ||Confidentiality: NONE|
| ||Integrity: NONE|
| ||Availability: COMPLETE|
The Linux kernel 2.6.20 and 2.6.21 does not properly handle an invalid LDT segment selector in %cs (the xcs field) during ptrace single-step operations, which allows local users to cause a denial of service (NULL dereference and OOPS) via certain code that makes ptrace PTRACE_SETREGS and PTRACE_SINGLESTEP requests, related to the TRACE_IRQS_ON function, and possibly related to the arch_ptrace function.