Ubuntu.comUB:CVE-2021-20194CVE-2021-20194
7.8 High
CVSS3
Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
4.6 Medium
CVSS2
Access Vector
LOCAL
Access Complexity
LOW
Authentication
NONE
Confidentiality Impact
PARTIAL
Integrity Impact
PARTIAL
Availability Impact
PARTIAL
AV:L/AC:L/Au:N/C:P/I:P/A:P
0.0004 Low
EPSS
Percentile
5.3%
There is a vulnerability in the linux kernel versions higher than 5.2 (if
kernel compiled with config params CONFIG_BPF_SYSCALL=y , CONFIG_BPF=y ,
CONFIG_CGROUPS=y , CONFIG_CGROUP_BPF=y , CONFIG_HARDENED_USERCOPY not set,
and BPF hook to getsockopt is registered). As result of BPF execution, the
local user can trigger bug in __cgroup_bpf_run_filter_getsockopt() function
that can lead to heap overflow (because of non-hardened usercopy). The
impact of attack could be deny of service or possibly privileges
escalation.
Notes
| Author | Note |
|---|---|
| sbeattie | for 5.8 kernels, HARDENED_USERCOPY is enabled, and so is less likely to be vulnerable to code execution. Also, user BPF is disabled if booted under secure boot/lockdown. |
| OS | Version | Architecture | Package | Version | Filename |
|---|---|---|---|---|---|
| ubuntu | 20.04 | noarch | linux-riscv-5.8 | < 5.8.0-18.20~20.04.1 | UNKNOWN |
| ubuntu | 20.04 | noarch | linux-bluefield | < 5.4.0-1011.14 | UNKNOWN |
| ubuntu | 20.10 | noarch | linux | < 5.8.0-45.51 | UNKNOWN |
| ubuntu | 20.04 | noarch | linux | < 5.4.0-71.79 | UNKNOWN |
| ubuntu | 18.04 | noarch | linux-hwe-5.4 | < 5.4.0-71.79~18.04.1 | UNKNOWN |
| ubuntu | 20.04 | noarch | linux-hwe-5.8 | < 5.8.0-45.51~20.04.1 | UNKNOWN |
| ubuntu | 20.04 | noarch | linux-kvm | < 5.4.0-1037.38 | UNKNOWN |
| ubuntu | 20.10 | noarch | linux-kvm | < 5.8.0-1020.22 | UNKNOWN |
| ubuntu | 18.04 | noarch | linux-aws-5.4 | < 5.4.0-1043.45~18.04.1 | UNKNOWN |
| ubuntu | 20.04 | noarch | linux-gkeop-5.15 | < any | UNKNOWN |
References
bugzilla.redhat.com/show_bug.cgi?id=1912683
launchpad.net/bugs/cve/CVE-2021-20194
nvd.nist.gov/vuln/detail/CVE-2021-20194
patchwork.kernel.org/project/netdevbpf/patch/[email protected]/#23921223
security-tracker.debian.org/tracker/CVE-2021-20194
ubuntu.com/security/notices/USN-4879-1
ubuntu.com/security/notices/USN-4884-1
ubuntu.com/security/notices/USN-4909-1
ubuntu.com/security/notices/USN-4912-1
www.cve.org/CVERecord?id=CVE-2021-20194
Related
7.8 High
CVSS3
Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
4.6 Medium
CVSS2
Access Vector
LOCAL
Access Complexity
LOW
Authentication
NONE
Confidentiality Impact
PARTIAL
Integrity Impact
PARTIAL
Availability Impact
PARTIAL
AV:L/AC:L/Au:N/C:P/I:P/A:P
0.0004 Low
EPSS
Percentile
5.3%