CVE-2021-28695
What it is
IOMMU page mapping issues on x86 T[his CNA information record relates to multiple CVEs; the text explains which aspects/vulnerabilities correspond to which CVE.] Both AMD and Intel allow ACPI tables to specify regions of memory which should be left untranslated, which typically means these addresses should pass the translation phase unaltered. While these are typically device specific ACPI properties, they can also be specified to apply to a range of devices, or even all devices. On all systems with such regions Xen failed to prevent guests from undoing/replacing such mappings (CVE-2021-28694). On AMD systems, where a discontinuous range is specified by firmware, the supposedly-excluded middle range will also be identity-mapped (CVE-2021-28695). Further, on AMD systems, upon de-assigment of a physical device from a guest, the identity mappings would be left in place, allowing a guest continued access to ranges of memory which it shouldn't have access to anymore (CVE-2021-28696).
At a glance
- Exploitability
- Can be exploited with physical access without logging in. High risk of data exposure, data tampering, service disruption.
- Exploit odds
- 0.4% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 0.4% in the next 30 days (EPSS).
- Severity: 6.8 MEDIUM (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 0.4% · EPSS, next 30 days
- Record status
- Modified
Affected
- Xen
- Fedoraproject Fedora 33
- Fedoraproject Fedora 34
- Fedoraproject Fedora 35
- Debian Linux 10.0
Attack profile CVSS 3.1 · 6.8
- Attack vector
- Physical
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Raw vector
CVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2021-28695.md and follow it. Check whether this project is affected by CVE-2021-28695. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
Fix and advisories
- https://xenbits.xenproject.org/xsa/advisory-378.txt
- https://xenbits.xenproject.org/xsa/advisory-378.txt
References
- http://www.openwall.com/lists/oss-security/2021/09/01/1
- http://www.openwall.com/lists/oss-security/2021/09/01/5
- http://www.openwall.com/lists/oss-security/2021/09/01/6
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2VQCFAPBNGBBAOMJZG6QBREOG5IIDZID/
- 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/LPRVHW4J4ZCPPOHZEWP5MOJT7XDGFFPJ/
- https://security.gentoo.org/glsa/202208-23
- https://www.debian.org/security/2021/dsa-4977
- https://xenbits.xenproject.org/xsa/advisory-378.txt
- http://www.openwall.com/lists/oss-security/2021/09/01/1
- http://www.openwall.com/lists/oss-security/2021/09/01/5
- http://www.openwall.com/lists/oss-security/2021/09/01/6
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2VQCFAPBNGBBAOMJZG6QBREOG5IIDZID/
- 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/LPRVHW4J4ZCPPOHZEWP5MOJT7XDGFFPJ/
- https://security.gentoo.org/glsa/202208-23
- https://www.debian.org/security/2021/dsa-4977
- https://xenbits.xenproject.org/xsa/advisory-378.txt