Privilege escalation in Xen
CVE-2020-29481
An issue was discovered in Xen through 4.14.x. Access rights of Xenstore nodes are per domid. Unfortunately, existing granted access rights are not removed when a domain is being destroyed. This means that a new domain created with the same domid will inherit the access rights to Xenstore nodes from the previous domain(s) with the same domid. Because all Xenstore entries of a guest below /local/domain/<domid> are being deleted by Xen tools when a guest is destroyed, only Xenstore entries of other guests still running are affected. For example, a newly created guest domain might be able to read sensitive information that had belonged to a previously existing guest domain. Both Xenstore implementations (C and Ocaml) are vulnerable.
Vulnerability class: Privilege Escalation
Published · last modified .
CVSS v3 metric
CVSS v3 base score 8.8 (High). Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H.
EPSS exploit prediction
EPSS: 0.004 (26.4th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 26th percentile — 26.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.003 · newest: 0.004 · change: +0.000
Affected products
- Xen
- Debian Linux — versions 10.0
- Fedoraproject Fedora — versions 32, 33
Weakness classification (CWE)
References
- xenbits.xenproject.org/xsa/advisory-322.html (Patch, Vendor Advisory)
- www.debian.org/security/2020/dsa-4812 (vendor-advisory, Third Party Advisory)
- www.openwall.com/lists/oss-security/2020/12/16/3 (mailing-list, Mailing List, Third Party Advisory)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory)
- lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/… (vendor-advisory)
Frequently asked questions
- What is CVE-2020-29481?
- CVE-2020-29481 is a high-severity vulnerability in Xen, classified under Improper Privilege Management. CVSS score: 8.8/10. Published 2020-12-15.
- How severe is CVE-2020-29481?
- High severity. CVSS v3 base score is 8.8 out of 10.