Vulnerability Name:

CVE-2019-20794 (CCN-182323)

Assigned:2019-02-28
Published:2019-02-28
Updated:2021-07-21
Summary:An issue was discovered in the Linux kernel 4.18 through 5.6.11 when unprivileged user namespaces are allowed. A user can create their own PID namespace, and mount a FUSE filesystem. Upon interaction with this FUSE filesystem, if the userspace component is terminated via a kill of the PID namespace's pid 1, it will result in a hung task, and resources being permanently locked up until system reboot. This can result in resource exhaustion.
CVSS v3 Severity:4.7 Medium (CVSS v3.1 Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H)
4.2 Medium (Temporal CVSS v3.1 Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H/E:U/RL:U/RC:R)
Exploitability Metrics:Attack Vector (AV): Local
Attack Complexity (AC): High
Privileges Required (PR): Low
User Interaction (UI): None
Scope:Scope (S): Unchanged
Impact Metrics:Confidentiality (C): None
Integrity (I): None
Availibility (A): High
5.5 Medium (CCN CVSS v3.1 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)
4.9 Medium (CCN Temporal CVSS v3.1 Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H/E:U/RL:U/RC:R)
Exploitability Metrics:Attack Vector (AV): Local
Attack Complexity (AC): Low
Privileges Required (PR): Low
User Interaction (UI): None
Scope:Scope (S): Unchanged
Impact Metrics:Confidentiality (C): None
Integrity (I): None
Availibility (A): High
CVSS v2 Severity:4.7 Medium (CVSS v2 Vector: AV:L/AC:M/Au:N/C:N/I:N/A:C)
Exploitability Metrics:Access Vector (AV): Local
Access Complexity (AC): Medium
Authentication (Au): None
Impact Metrics:Confidentiality (C): None
Integrity (I): None
Availibility (A): Complete
4.6 Medium (CCN CVSS v2 Vector: AV:L/AC:L/Au:S/C:N/I:N/A:C)
Exploitability Metrics:Access Vector (AV): Local
Access Complexity (AC): Low
Athentication (Au): Single_Instance
Impact Metrics:Confidentiality (C): None
Integrity (I): None
Availibility (A): Complete
Vulnerability Type:CWE-400
Vulnerability Consequences:Denial of Service
References:Source: MITRE
Type: CNA
CVE-2019-20794

Source: MLIST
Type: Mailing List, Third Party Advisory
[oss-security] 20200824 CVE-2019-20794 kernel: task processes not being properly ended could lead to resource exhaustion

Source: XF
Type: UNKNOWN
linux-kernel-cve201920794-dos(182323)

Source: CCN
Type: GitHub Web site
FUSE

Source: CONFIRM
Type: Exploit, Third Party Advisory
https://github.com/sargun/fuse-example

Source: CONFIRM
Type: Third Party Advisory
https://security.netapp.com/advisory/ntap-20200608-0001/

Source: CONFIRM
Type: Exploit, Third Party Advisory
https://sourceforge.net/p/fuse/mailman/message/36598753/

Source: CCN
Type: Linux Kernel Web site
The Linux Kernel Archives

Vulnerable Configuration:Configuration 1:
  • cpe:/o:linux:linux_kernel:*:*:*:*:*:*:*:* (Version >= 4.18 and <= 5.6.11)

    • Configuration CCN 1:
  • cpe:/o:linux:linux_kernel:4.18:-:*:*:*:*:*:*
  • OR cpe:/o:linux:linux_kernel:5.6.11:*:*:*:*:*:*:*

    • * Denotes that component is vulnerable
    BACK
    linux linux kernel *
    linux linux kernel 4.18
    linux linux kernel 5.6.11