Vulnerability in Xen
CVE-2022-26362
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.
Vulnerability class: Race Condition
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.4 (Medium). Vector: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.004 (29.5th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 29th percentile — 29.5% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.004 · change: 0.000
Affected products
- Xen — versions consult Xen advisory XSA-401
- Debian Linux — versions 11.0
- Fedoraproject Fedora — versions 35, 36
Weakness classification (CWE)
References
- xenbits.xenproject.org/xsa/advisory-401.txt (Vendor Advisory)
- xenbits.xen.org/xsa/advisory-401.html (Patch, Vendor Advisory)
- www.openwall.com/lists/oss-security/2022/06/09/3 (mailing-list, Mailing List, Third Party Advisory)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory)
- packetstormsecurity.com/files/167718/Xen-TLB-Flush-Bypass.html (VDB Entry, Third Party Advisory)
- www.debian.org/security/2022/dsa-5184 (vendor-advisory, Third Party Advisory)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory)
- security.gentoo.org/glsa/202208-23 (vendor-advisory, Third Party Advisory)
Frequently asked questions
- What is CVE-2022-26362?
- CVE-2022-26362 is a medium-severity vulnerability in Xen, classified under Concurrent Execution using Shared Resource with Improper Synchronization (Race Condition). CVSS score: 6.4/10. Published 2022-06-09.
- How severe is CVE-2022-26362?
- Medium severity. CVSS v3 base score is 6.4 out of 10.