CVE-2021-28701
Published: 8 September 2021
Another race in XENMAPSPACE_grant_table handling Guests are 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, are de-allocated when a guest switches (back) from v2 to v1. Freeing such pages requires that the hypervisor enforce that no parallel request can result in the addition of a mapping of such a page to a guest. That enforcement was missing, allowing guests to retain access to pages that were freed and perhaps re-used for other purposes. Unfortunately, when XSA-379 was being prepared, this similar issue was not noticed.
CVSS 3 base score: 7.8
Notes
Author | Note |
---|---|
mdeslaur | hypervisor packages are in universe. For issues in the hypervisor, add appropriate tags to each section, ex: Tags_xen: universe-binary |
References
- https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-28701
- https://xenbits.xen.org/xsa/advisory-384.html
- https://xenbits.xenproject.org/xsa/advisory-384.txt
- http://xenbits.xen.org/xsa/advisory-384.html
- http://www.openwall.com/lists/oss-security/2021/09/08/2
- NVD
- Launchpad
- Debian