CVE-2020-29571: Null Pointer Dereference
First published: Tue Dec 15 2020(Updated: )
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.
Credit: cve@mitre.org
| Affected Software | Affected Version | How to fix |
|---|---|---|
| debian/xen | 4.11.4+107-gef32c7afa2-1 4.14.6-1 4.14.5+94-ge49571868d-1 4.17.1+2-gb773c48e36-1 4.17.2+55-g0b56bed864-1 | |
| Xen Xen | >=4.4.0<=4.14.0 | |
| Debian Debian Linux | =10.0 | |
| Fedoraproject Fedora | =32 | |
| Fedoraproject Fedora | =33 |
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Reference Links
- https://xenbits.xen.org/xsa/advisory-359.html
- https://security-tracker.debian.org/tracker/CVE-2020-29571
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/2C6M6S3CIMEBACH6O7V4H2VDANMO6TVA/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/OBLV6L6Q24PPQ2CRFXDX4Q76KU776GKI/
- https://security.gentoo.org/glsa/202107-30
- https://www.debian.org/security/2020/dsa-4812
- https://xenbits.xenproject.org/xsa/advisory-359.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/OBLV6L6Q24PPQ2CRFXDX4Q76KU776GKI/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2C6M6S3CIMEBACH6O7V4H2VDANMO6TVA/
- collector/security-tracker-debian
- collector/nvd-index
- agent/severity
- agent/references
- agent/weakness
- agent/author
- agent/type
- agent/description
- agent/event
- agent/first-publish-date
- agent/softwarecombine
- agent/last-modified-date
- agent/remedy
- agent/tags
- collector/mitre-cve
- source/MITRE
- package-manager/debian
- vendor/xen
- canonical/xen xen
- version/xen xen/4.4.0
- version/xen xen/4.14.0
- vendor/debian
- canonical/debian debian linux
- version/debian debian linux/10.0
- vendor/fedoraproject
- canonical/fedoraproject fedora
- version/fedoraproject fedora/32
- version/fedoraproject fedora/33