CVE-2021-28697: Race Condition
First published: Fri Aug 27 2021(Updated: )
grant table v2 status pages may remain accessible after de-allocation Guest get permitted access to certain Xen-owned pages of memory. The majority of such pages remain allocated / associated with a guest for its entire lifetime. Grant table v2 status pages, however, get de-allocated when a guest switched (back) from v2 to v1. The freeing of such pages requires that the hypervisor know where in the guest these pages were mapped. The hypervisor tracks only one use within guest space, but racing requests from the guest to insert mappings of these pages may result in any of them to become mapped in multiple locations. Upon switching back from v2 to v1, the guest would then retain access to a page that was freed and perhaps re-used for other purposes.
Credit: security@xen.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-unstable | >=4.0.0<=4.15.0 | |
| Fedora | =33 | |
| Fedora | =34 | |
| Fedora | =35 | |
| Debian | =11.0 |
Never miss a vulnerability like this again
Sign up to SecAlerts for real-time vulnerability data matched to your software, aggregated from hundreds of sources.
Reference Links
- https://xenbits.xen.org/xsa/advisory-379.html
- https://security-tracker.debian.org/tracker/CVE-2021-28697
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/2VQCFAPBNGBBAOMJZG6QBREOG5IIDZID/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/FZCNPSRPGFCQRYE2BI4D4Q4SCE56ANV2/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/LPRVHW4J4ZCPPOHZEWP5MOJT7XDGFFPJ/
- https://security.gentoo.org/glsa/202208-23
- https://www.debian.org/security/2021/dsa-4977
- https://xenbits.xenproject.org/xsa/advisory-379.txt
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/LPRVHW4J4ZCPPOHZEWP5MOJT7XDGFFPJ/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/FZCNPSRPGFCQRYE2BI4D4Q4SCE56ANV2/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2VQCFAPBNGBBAOMJZG6QBREOG5IIDZID/
Frequently Asked Questions
What is the vulnerability ID of this issue?
The vulnerability ID is CVE-2021-28697.
What is the severity level of CVE-2021-28697?
The severity level of CVE-2021-28697 is high with a severity value of 7.8.
What is the affected software for CVE-2021-28697?
The affected software includes Xen Xen, Fedoraproject Fedora (versions 33, 34, and 35), and Debian Debian Linux (version 11.0).
How can I fix CVE-2021-28697?
To fix CVE-2021-28697, you should update your Xen, Fedoraproject Fedora, or Debian Debian Linux to the specified versions that contain the necessary remedies.
Where can I find more information about CVE-2021-28697?
More information about CVE-2021-28697 can be found in the XSA advisory, Debian Security Tracker, and Fedoraproject mailing list.
- collector/security-tracker-debian
- agent/type
- collector/mitre-cve
- source/MITRE
- agent/severity
- agent/weakness
- agent/author
- agent/references
- agent/last-modified-date
- agent/description
- agent/first-publish-date
- agent/event
- agent/source
- agent/tags
- agent/softwarecombine
- collector/nvd-index
- agent/software-canonical-lookup-request
- package-manager/debian
- vendor/xen
- canonical/xen xen-unstable
- version/xen xen-unstable/4.0.0
- version/xen xen-unstable/4.15.0
- vendor/fedoraproject
- canonical/fedora
- version/fedora/33
- version/fedora/34
- version/fedora/35
- vendor/debian
- canonical/debian
- version/debian/11.0