Vulnerability Details : CVE-2021-4095
A NULL pointer dereference was found in the Linux kernel's KVM when dirty ring logging is enabled without an active vCPU context. An unprivileged local attacker on the host may use this flaw to cause a kernel oops condition and thus a denial of service by issuing a KVM_XEN_HVM_SET_ATTR ioctl. This flaw affects Linux kernel versions prior to 5.17-rc1.
Vulnerability category: Memory CorruptionDenial of service
Exploit prediction scoring system (EPSS) score for CVE-2021-4095
Probability of exploitation activity in the next 30 days: 0.04%
Percentile, the proportion of vulnerabilities that are scored at or less: ~ 6 % EPSS Score History EPSS FAQ
CVSS scores for CVE-2021-4095
| Base Score | Base Severity | CVSS Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|
|
1.9
|
LOW | AV:L/AC:M/Au:N/C:N/I:N/A:P |
3.4
|
2.9
|
nvd@nist.gov |
|
5.5
|
MEDIUM | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
1.8
|
3.6
|
nvd@nist.gov |
CWE ids for CVE-2021-4095
-
A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit.Assigned by:
- nvd@nist.gov (Primary)
- secalert@redhat.com (Secondary)
References for CVE-2021-4095
-
https://bugzilla.redhat.com/show_bug.cgi?id=2031194
2031194 – (CVE-2021-4095) CVE-2021-4095 kernel: KVM: NULL pointer dereference in kvm_dirty_ring_get() in virt/kvm/dirty_ring.cExploit;Issue Tracking;Patch;Third Party Advisory
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https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/VT6573CGKVK3DU2632VVO5BVM4IU7SBV/
[SECURITY] Fedora 35 Update: kernel-5.17.4-200.fc35 - package-announce - Fedora Mailing-ListsMailing List;Third Party Advisory
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http://www.openwall.com/lists/oss-security/2022/01/17/1
oss-security - Re: CVE-2021-4095: kernel: KVM: NULL pointer dereference in kvm_dirty_ring_get() in virt/kvm/dirty_ring.cExploit;Mailing List;Patch;Third Party Advisory
-
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/QIOQN7JJNN6ABIDGRSTVZA65MHRLMH2Q/
[SECURITY] Fedora 34 Update: kernel-tools-5.17.4-100.fc34 - package-announce - Fedora Mailing-ListsMailing List;Third Party Advisory
Products affected by CVE-2021-4095
- cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
- cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
- cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*