CVE-2021-28701

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 v3.0 7.8 HIGH
CVSS v2.0 4.4 MEDIUM

7.8^/10

CVSS v3.0 : HIGH

V3 Legend

Vector :

Exploitability : 1.1 / Impact : 6.0

Attack Vector LOCAL

Attack Complexity HIGH

Privileges Required LOW

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope CHANGED

4.4^/10

CVSS v2.0 : MEDIUM

V2 Legend

Vector : AV:L/AC:M/Au:N/C:P/I:P/A:P

Exploitability : 3.4 / Impact : 6.4

Access Vector LOCAL

Access Complexity MEDIUM

Authentication NONE

Confidentiality Impact PARTIAL

Integrity Impact PARTIAL

Availability Impact PARTIAL

References

Link	Resource
https://xenbits.xenproject.org/xsa/advisory-384.txt	Vendor Advisory
http://xenbits.xen.org/xsa/advisory-384.html	Vendor Advisory
http://www.openwall.com/lists/oss-security/2021/09/08/2	Mailing List Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/L4MI3MQAPGILCLXBGQWPZHGE3ALSO4ZU/	Mailing List Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/CEHZLIR5DFYYQBH55AERWHLO54OFU42C/	Mailing List Third Party Advisory
https://www.debian.org/security/2021/dsa-4977	Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/3HEHUIUWSSMCQGQY3GWX4J2SZGYP5W2Z/	Mailing List Third Party Advisory
https://security.gentoo.org/glsa/202208-23	Third Party Advisory

Configurations

Configuration 1 (hide)

cpe:2.3:o:xen:xen:*:*:*:*:*:*:*:*

Configuration 2 (hide)

cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*

Configuration 3 (hide)

OR	cpe:2.3:o:fedoraproject:fedora:33:::::::*
	cpe:2.3:o:fedoraproject:fedora:34:::::::*
	cpe:2.3:o:fedoraproject:fedora:35:::::::*

Information

Published : 2021-09-08 07:15

Updated : 2022-10-28 09:20

NVD link : CVE-2021-28701

Mitre link : CVE-2021-28701

JSON object : View

CWE

CWE-362

Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

Products Affected

debian

debian_linux

xen

fedoraproject

fedora

{"cve": {"data_type": "CVE", "references": {"reference_data": [{"url": "https://xenbits.xenproject.org/xsa/advisory-384.txt", "name": "https://xenbits.xenproject.org/xsa/advisory-384.txt", "tags": ["Vendor Advisory"], "refsource": "MISC"}, {"url": "http://xenbits.xen.org/xsa/advisory-384.html", "name": "http://xenbits.xen.org/xsa/advisory-384.html", "tags": ["Vendor Advisory"], "refsource": "CONFIRM"}, {"url": "http://www.openwall.com/lists/oss-security/2021/09/08/2", "name": "[oss-security] 20210908 Xen Security Advisory 384 v3 (CVE-2021-28701) - Another race in XENMAPSPACE_grant_table handling", "tags": ["Mailing List", "Third Party Advisory"], "refsource": "MLIST"}, {"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/L4MI3MQAPGILCLXBGQWPZHGE3ALSO4ZU/", "name": "FEDORA-2021-11577e5229", "tags": ["Mailing List", "Third Party Advisory"], "refsource": "FEDORA"}, {"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/CEHZLIR5DFYYQBH55AERWHLO54OFU42C/", "name": "FEDORA-2021-fed53cbc7d", "tags": ["Mailing List", "Third Party Advisory"], "refsource": "FEDORA"}, {"url": "https://www.debian.org/security/2021/dsa-4977", "name": "DSA-4977", "tags": ["Third Party Advisory"], "refsource": "DEBIAN"}, {"url": "https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/3HEHUIUWSSMCQGQY3GWX4J2SZGYP5W2Z/", "name": "FEDORA-2021-5a0c7bc619", "tags": ["Mailing List", "Third Party Advisory"], "refsource": "FEDORA"}, {"url": "https://security.gentoo.org/glsa/202208-23", "name": "GLSA-202208-23", "tags": ["Third Party Advisory"], "refsource": "GENTOO"}]}, "data_format": "MITRE", "description": {"description_data": [{"lang": "en", "value": "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."}]}, "problemtype": {"problemtype_data": [{"description": [{"lang": "en", "value": "CWE-362"}]}]}, "data_version": "4.0", "CVE_data_meta": {"ID": "CVE-2021-28701", "ASSIGNER": "security@xen.org"}}, "impact": {"baseMetricV2": {"cvssV2": {"version": "2.0", "baseScore": 4.4, "accessVector": "LOCAL", "vectorString": "AV:L/AC:M/Au:N/C:P/I:P/A:P", "authentication": "NONE", "integrityImpact": "PARTIAL", "accessComplexity": "MEDIUM", "availabilityImpact": "PARTIAL", "confidentialityImpact": "PARTIAL"}, "severity": "MEDIUM", "acInsufInfo": false, "impactScore": 6.4, "obtainAllPrivilege": false, "exploitabilityScore": 3.4, "obtainUserPrivilege": false, "obtainOtherPrivilege": false, "userInteractionRequired": false}, "baseMetricV3": {"cvssV3": {"scope": "CHANGED", "version": "3.1", "baseScore": 7.8, "attackVector": "LOCAL", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "HIGH", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "HIGH"}, "impactScore": 6.0, "exploitabilityScore": 1.1}}, "publishedDate": "2021-09-08T14:15Z", "configurations": {"nodes": [{"children": [], "operator": "OR", "cpe_match": [{"cpe23Uri": "cpe:2.3:o:xen:xen:*:*:*:*:*:*:*:*", "cpe_name": [], "vulnerable": true, "versionStartIncluding": "4.0.0"}]}, {"children": [], "operator": "OR", "cpe_match": [{"cpe23Uri": "cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*", "cpe_name": [], "vulnerable": true}]}, {"children": [], "operator": "OR", "cpe_match": [{"cpe23Uri": "cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*", "cpe_name": [], "vulnerable": true}, {"cpe23Uri": "cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*", "cpe_name": [], "vulnerable": true}, {"cpe23Uri": "cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*", "cpe_name": [], "vulnerable": true}]}], "CVE_data_version": "4.0"}, "lastModifiedDate": "2022-10-28T16:20Z"}

7.8 /10