CVE-2020-29569
A misbehaving guest can trigger a dom0 crash by continuously connecting / disconnecting a block frontend.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.39%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
An issue was discovered in the Linux kernel through 5.10.1, as used with Xen through 4.14.x. The Linux kernel PV block backend expects the kernel thread handler to reset ring->xenblkd to NULL when stopped. However, the handler may not have time to run if the frontend quickly toggles between the states connect and disconnect. As a consequence, the block backend may re-use a pointer after it was freed. A misbehaving guest can trigger a dom0 crash by continuously connecting / disconnecting a block frontend. Privilege escalation and information leaks cannot be ruled out. This only affects systems with a Linux blkback.
- CVSS 3.1
- 8.8 HIGHCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
- EPSS
- 0.39% probability · 33th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-416
- Affected
- xen/xen · linux/linux kernel · netapp/hci compute node bios · netapp/solidfire \& hci management node · netapp/solidfire \& hci storage node · debian/debian linux
- Source
- cve@mitre.org
References
- https://lists.debian.org/debian-lts-announce/2021/02/msg00018.htmlMailing List, Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2021/03/msg00010.htmlMailing List, Third Party Advisory
- https://security.gentoo.org/glsa/202107-30Third Party Advisory
- https://security.netapp.com/advisory/ntap-20210205-0001/Third Party Advisory
- https://www.debian.org/security/2021/dsa-4843Third Party Advisory
- https://xenbits.xenproject.org/xsa/advisory-350.htmlPatch, Vendor Advisory
- https://lists.debian.org/debian-lts-announce/2021/02/msg00018.htmlMailing List, Third Party Advisory
- https://lists.debian.org/debian-lts-announce/2021/03/msg00010.htmlMailing List, Third Party Advisory
- https://security.gentoo.org/glsa/202107-30Third Party Advisory
- https://security.netapp.com/advisory/ntap-20210205-0001/Third Party Advisory
- https://www.debian.org/security/2021/dsa-4843Third Party Advisory
- https://xenbits.xenproject.org/xsa/advisory-350.htmlPatch, Vendor Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.