Vulnerability · Published Mar 8, 2022 · Assigned by redhat
CVE-2021-4095
Medium 5.5
In plain English
A medium-severity null pointer dereference in kernel. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.4% (higher than 33% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS NVD)5.5Medium
Exploit odds (30 days)0.4%top 67.0% of all CVEs
Exploited in the wildNo reportsnot in CISA KEV
Attack toolingNoneno public tooling known
Official description
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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | linux | 5.17.3-1 | DEBIAN-CVE-2021-4095 |
| Debian:13 | linux | 5.17.3-1 | DEBIAN-CVE-2021-4095 |
| Debian:14 | linux | 5.17.3-1 | DEBIAN-CVE-2021-4095 |
| Ubuntu:22.04:LTS | linux | no fix listed | UBUNTU-CVE-2021-4095 |
| Ubuntu:22.04:LTS | linux-aws | no fix listed | UBUNTU-CVE-2021-4095 |
| Ubuntu:22.04:LTS | linux-azure | no fix listed | UBUNTU-CVE-2021-4095 |
| Ubuntu:22.04:LTS | linux-azure-fde | no fix listed | UBUNTU-CVE-2021-4095 |
| Ubuntu:22.04:LTS | linux-gcp | no fix listed | UBUNTU-CVE-2021-4095 |
| Ubuntu:22.04:LTS | linux-gke | no fix listed | UBUNTU-CVE-2021-4095 |
| Ubuntu:22.04:LTS | linux-gkeop | no fix listed | UBUNTU-CVE-2021-4095 |
| Ubuntu:22.04:LTS | linux-ibm | no fix listed | UBUNTU-CVE-2021-4095 |
| Ubuntu:22.04:LTS | linux-intel-iot-realtime | no fix listed | UBUNTU-CVE-2021-4095 |
| Ubuntu:22.04:LTS | linux-intel-iotg | no fix listed | UBUNTU-CVE-2021-4095 |
| Ubuntu:22.04:LTS | linux-kvm | no fix listed | UBUNTU-CVE-2021-4095 |
| Ubuntu:22.04:LTS | linux-lowlatency | no fix listed | UBUNTU-CVE-2021-4095 |
| Ubuntu:22.04:LTS | linux-nvidia | no fix listed | UBUNTU-CVE-2021-4095 |
| Ubuntu:22.04:LTS | linux-nvidia-tegra | no fix listed | UBUNTU-CVE-2021-4095 |
| Ubuntu:22.04:LTS | linux-nvidia-tegra-igx | no fix listed | UBUNTU-CVE-2021-4095 |
| Ubuntu:22.04:LTS | linux-oracle | no fix listed | UBUNTU-CVE-2021-4095 |
| Ubuntu:22.04:LTS | linux-raspi | no fix listed | UBUNTU-CVE-2021-4095 |
| Ubuntu:24.04:LTS | linux-raspi-realtime | no fix listed | UBUNTU-CVE-2021-4095 |
| Ubuntu:22.04:LTS | linux-realtime | no fix listed | UBUNTU-CVE-2021-4095 |
| Ubuntu:22.04:LTS | linux-riscv | no fix listed | UBUNTU-CVE-2021-4095 |
| Ubuntu:22.04:LTS | linux-xilinx-zynqmp | no fix listed | UBUNTU-CVE-2021-4095 |
Affected products (as reported)
Weakness: CWE-476
References
- [oss-security] 20220117 Re: CVE-2021-4095: kernel: KVM: NULL pointer dereference in kvm_dirty_ring_get() in virt/kvm/dirty_ring.c mailing-list, x_refsource_MLIST
- https://bugzilla.redhat.com/show_bug.cgi?id=2031194 x_refsource_MISC
- FEDORA-2022-0816754490 vendor-advisory, x_refsource_FEDORA
- FEDORA-2022-8efcea6e67 vendor-advisory, x_refsource_FEDORA