Xen
CVE-2020-29479
HIGH
Severity by source
AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Lifecycle Timeline
1DescriptionNVD
An issue was discovered in Xen through 4.14.x. In the Ocaml xenstored implementation, the internal representation of the tree has special cases for the root node, because this node has no parent. Unfortunately, permissions were not checked for certain operations on the root node. Unprivileged guests can get and modify permissions, list, and delete the root node. (Deleting the whole xenstore tree is a host-wide denial of service.) Achieving xenstore write access is also possible. All systems using oxenstored are vulnerable. Building and using oxenstored is the default in the upstream Xen distribution, if the Ocaml compiler is available. Systems using C xenstored are not vulnerable.
AnalysisAI
An issue was discovered in Xen through 4.14.x. Rated high severity (CVSS 8.8), this vulnerability is low attack complexity. This Missing Authorization vulnerability could allow attackers to access resources or perform actions without proper authorization checks.
Technical ContextAI
This vulnerability is classified as Missing Authorization (CWE-862), which allows attackers to access resources or perform actions without proper authorization checks. An issue was discovered in Xen through 4.14.x. In the Ocaml xenstored implementation, the internal representation of the tree has special cases for the root node, because this node has no parent. Unfortunately, permissions were not checked for certain operations on the root node. Unprivileged guests can get and modify permissions, list, and delete the root node. (Deleting the whole xenstore tree is a host-wide denial of service.) Achieving xenstore write access is also possible. All systems using oxenstored are vulnerable. Building and using oxenstored is the default in the upstream Xen distribution, if the Ocaml compiler is available. Systems using C xenstored are not vulnerable. Affected products include: Xen, Debian Debian Linux, Fedoraproject Fedora. Version information: through 4.14..
RemediationAI
A vendor patch is available. Apply the latest security update as soon as possible. Implement role-based access control, validate authorization on every request server-side, apply principle of least privilege.
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Same weakness CWE-862 – Missing Authorization
View allSame technique Denial Of Service
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External POC / Exploit Code
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