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xenXen ProjectXSA-331
HistoryOct 20, 2020 - 11:49 a.m.

Race condition in Linux event handler may crash dom0

2020-10-2011:49:00
Xen Project
xenbits.xen.org
32

4.7 Medium

CVSS3

Attack Vector

LOCAL

Attack Complexity

HIGH

Privileges Required

LOW

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

HIGH

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

4.7 Medium

CVSS2

Access Vector

LOCAL

Access Complexity

MEDIUM

Authentication

NONE

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

COMPLETE

AV:L/AC:M/Au:N/C:N/I:N/A:C

0.0004 Low

EPSS

Percentile

13.2%

ISSUE DESCRIPTION

The Linux kernel event channel handling code doesn’t defend the handling of an event against the same event channel being removed in parallel.
This can result in accesses to already freed memory areas or NULL pointer dereferences in the event handling code, leading to misbehaviour of the system or even crashes.

IMPACT

A misbehaving guest can trigger a dom0 crash by sending events for a paravirtualized device while simultaneously reconfiguring it.

VULNERABLE SYSTEMS

All systems with a Linux dom0 are vulnerable.
All Linux kernel versions are vulnerable.

4.7 Medium

CVSS3

Attack Vector

LOCAL

Attack Complexity

HIGH

Privileges Required

LOW

User Interaction

NONE

Scope

UNCHANGED

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

HIGH

CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H

4.7 Medium

CVSS2

Access Vector

LOCAL

Access Complexity

MEDIUM

Authentication

NONE

Confidentiality Impact

NONE

Integrity Impact

NONE

Availability Impact

COMPLETE

AV:L/AC:M/Au:N/C:N/I:N/A:C

0.0004 Low

EPSS

Percentile

13.2%