CVE-2022-26362

medium

Description

x86 pv: Race condition in typeref acquisition Xen maintains a type reference count for pages, in addition to a regular reference count. This scheme is used to maintain invariants required for Xen's safety, e.g. PV guests may not have direct writeable access to pagetables; updates need auditing by Xen. Unfortunately, the logic for acquiring a type reference has a race condition, whereby a safely TLB flush is issued too early and creates a window where the guest can re-establish the read/write mapping before writeability is prohibited.

References

http://www.openwall.com/lists/oss-security/2022/06/09/3

https://xenbits.xenproject.org/xsa/advisory-401.txt

http://xenbits.xen.org/xsa/advisory-401.html

https://lists.fedoraproject.org/archives/list/[email protected]/message/OH65U6FTTB5MLH5A6Q3TW7KVCGOG4MYI/

http://packetstormsecurity.com/files/167718/Xen-TLB-Flush-Bypass.html

https://www.debian.org/security/2022/dsa-5184

https://lists.fedoraproject.org/archives/list/[email protected]/message/RKRXZ4LHGCGMOG24ZCEJNY6R2BTS4S2Q/

https://security.gentoo.org/glsa/202208-23

Details

Source: MITRE

Published: 2022-06-09

Updated: 2022-08-24

Type: CWE-362

Risk Information

CVSS v2

Base Score: 6.9

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

Impact Score: 10

Exploitability Score: 3.4

Severity: MEDIUM

CVSS v3

Base Score: 6.4

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

Impact Score: 5.9

Exploitability Score: 0.5

Severity: MEDIUM