CVE-2020-29571: debian debian_linux NULL Pointer Dereference
Vulnerability summary
CVE-2020-29571 is a medium (CVSS 6.2) NULL Pointer Dereference vulnerability in debian debian_linux. EPSS estimates a 0.39% chance of exploitation in the next 30 days, higher than 32.8% of scored vulnerabilities.
Not severe (CVSS 6.2, local access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 12 · Related 11Timeline
- 15-12-2020PublishedVulnerability first disclosed.
- 04-08-2024Last modifiedVulnerability information updated.
Description
An issue was discovered in Xen through 4.14.x. A bounds check common to most operation time functions specific to FIFO event channels depends on the CPU observing consistent state. While the producer side uses appropriately ordered writes, the consumer side isn't protected against re-ordered reads, and may hence end up de-referencing a NULL pointer. Malicious or buggy guest kernels can mount a Denial of Service (DoS) attack affecting the entire system. Only Arm systems may be vulnerable. Whether a system is vulnerable depends on the specific CPU. x86 systems are not vulnerable.
CVSS metrics
5 scores · 4 sources · 2 versions- OSV · AlpineEcosystem advisory · calculated6.2MediumCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · UbuntuEcosystem advisory · calculated6.2MediumCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · DebianEcosystem advisory · calculated6.2MediumCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
0.39%
Chance of exploitation in the next 30 days
Percentile
33%
Versus all other CVEs
30-day change
No change 0.00 pp
From 0.38% 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, no authentication, 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≥ 4.4.0, < 4.13.2-r3 | ≥ 4.4.0, < 4.14.1-r0
Fedoraproject1 product
- fedoraEOL32 | 33
Ubuntu1 product
- xenAll versions (No fix recorded)
Xen1 product
- xen≥ 4.4.0, ≤ 4.14.0
5 vendors · 6 products
