CVE-2020-29479: debian debian_linux Missing Authorization
Vulnerability summary
CVE-2020-29479 is a high (CVSS 8.8) Missing Authorization vulnerability in debian debian_linux. EPSS estimates a 0.31% chance of exploitation in the next 30 days, higher than 23.6% of scored vulnerabilities.
Not severe (CVSS 8.8, local access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 1Timeline
- 15-12-2020PublishedVulnerability first disclosed.
- 04-08-2024Last modifiedVulnerability information updated.
Description
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.
CVSS metrics
5 scores · 4 sources · 2 versions- OSV · AlpineEcosystem advisory · calculated8.8HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
- OSV · UbuntuEcosystem advisory · calculated8.8HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
- OSV · DebianEcosystem advisory · calculated8.8HighCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
EPSS trend
Probability
0.31%
Chance of exploitation in the next 30 days
Percentile
24%
Versus all other CVEs
30-day change
No change 0.00 pp
From 0.31% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Known conditions: local access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.
Debian2 products
- xen< 4.14.0+88-g1d1d1f5391-1
- debian_linuxEOL10.0
Alpine1 product
- xen< 4.13.2-r3 | < 4.14.1-r0
Fedoraproject1 product
- fedoraEOL32 | 33
Ubuntu1 product
- xenAll versions (No fix recorded)
Xen1 product
- xen≤ 4.14.0
5 vendors · 6 products
