CVE-2022-33745
CVE-2022-33745 is a high-severity vulnerability in Xen with a CVSS 3.x base score of 8.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low.
Key facts
- Severity: High (CVSS 3.x base score 8.8)
- EPSS exploit prediction: 0% (21st percentile)
- Actively exploited: Not listed in CISA KEV
- Affected product: Xen
- Published:
- Last modified:
Description
insufficient TLB flush for x86 PV guests in shadow mode For migration as well as to work around kernels unaware of L1TF (see XSA-273), PV guests may be run in shadow paging mode. To address XSA-401, code was moved inside a function in Xen. This code movement missed a variable changing meaning / value between old and new code positions. The now wrong use of the variable did lead to a wrong TLB flush condition, omitting flushes where such are necessary.
Frequently asked questions
- What is CVE-2022-33745?
- insufficient TLB flush for x86 PV guests in shadow mode For migration as well as to work around kernels unaware of L1TF (see XSA-273), PV guests may be run in shadow paging mode. To address XSA-401, code was moved inside a function in Xen. This code movement missed a variable changing meaning / value between old and new code positions. The now wrong use of the variable did lead to a wrong TLB flush condition, omitting flushes where such are necessary.
- How severe is CVE-2022-33745?
- CVE-2022-33745 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
- Is CVE-2022-33745 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (21st percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2022-33745?
- CVE-2022-33745 primarily affects Xen. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
- How do I fix CVE-2022-33745?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- When was CVE-2022-33745 published?
- CVE-2022-33745 was published on 2022-07-26 and last updated on 2026-06-17.
References
- http://www.openwall.com/lists/oss-security/2022/07/26/2
- http://www.openwall.com/lists/oss-security/2022/07/26/3
- http://xenbits.xen.org/xsa/advisory-408.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HUFIMNGYP5VQAA6KE3T2I5GW6UP6F7BS/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/MYI3OMJ7RIZNL3C6GUWNANNPEUUID6FM/
- https://www.debian.org/security/2022/dsa-5272
- https://xenbits.xenproject.org/xsa/advisory-408.txt
Affected products (4)
- cpe:2.3:o:xen:xen:*:*:*:*:*:*:x86:*
- cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*
- cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*
- cpe:2.3:o:fedoraproject:fedora:36:*:*:*:*:*:*:*
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