Vulnerability Name:

CVE-2021-20261 (CCN-198070)

Assigned:2020-12-17
Published:2021-03-11
Updated:2021-03-19
Summary:A race condition was found in the Linux kernels implementation of the floppy disk drive controller driver software. The impact of this issue is lessened by the fact that the default permissions on the floppy device (/dev/fd0) are restricted to root. If the permissions on the device have changed the impact changes greatly. In the default configuration root (or equivalent) permissions are required to attack this flaw.
CVSS v3 Severity:6.4 Medium (CVSS v3.1 Vector: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H)
5.6 Medium (Temporal CVSS v3.1 Vector: CVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C)
Exploitability Metrics:Attack Vector (AV): Local
Attack Complexity (AC): High
Privileges Required (PR): High
User Interaction (UI): None
Scope:Scope (S): Unchanged
Impact Metrics:Confidentiality (C): High
Integrity (I): High
Availibility (A): High
6.7 Medium (CCN CVSS v3.1 Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H)
5.8 Medium (CCN Temporal CVSS v3.1 Vector: CVSS:3.1/AV:L/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C)
Exploitability Metrics:Attack Vector (AV): Local
Attack Complexity (AC): Low
Privileges Required (PR): High
User Interaction (UI): None
Scope:Scope (S): Unchanged
Impact Metrics:Confidentiality (C): High
Integrity (I): High
Availibility (A): High
CVSS v2 Severity:4.4 Medium (CVSS v2 Vector: AV:L/AC:M/Au:N/C:P/I:P/A:P)
Exploitability Metrics:Access Vector (AV): Local
Access Complexity (AC): Medium
Authentication (Au): None
Impact Metrics:Confidentiality (C): Partial
Integrity (I): Partial
Availibility (A): Partial
6.8 Medium (CCN CVSS v2 Vector: AV:L/AC:L/Au:S/C:C/I:C/A:C)
Exploitability Metrics:Access Vector (AV): Local
Access Complexity (AC): Low
Athentication (Au): Single_Instance
Impact Metrics:Confidentiality (C): Complete
Integrity (I): Complete
Availibility (A): Complete
Vulnerability Type:CWE-362
Vulnerability Consequences:Denial of Service
References:Source: MITRE
Type: CNA
CVE-2021-20261

Source: MISC
Type: Issue Tracking, Patch, Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=1932150

Source: XF
Type: UNKNOWN
linux-kernel-cve202120261-dos(198070)

Source: CCN
Type: Linux Kernel GIT Repository
floppy: fix lock_fdc() signal handling

Source: MISC
Type: Mailing List, Patch, Vendor Advisory
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=a0c80efe5956ccce9fe7ae5c78542578c07bc20a

Source: CCN
Type: oss-sec Mailing List, Thu, 11 Mar 2021 15:59:47 +1000
CVE-2021-20261: kernel: panic in start_motor+0x21 when /dev/fd0 is read by multiple threads.

Vulnerable Configuration:Configuration 1:
  • cpe:/o:linux:linux_kernel:*:*:*:*:*:*:*:* (Version < 4.5)
  • OR cpe:/o:linux:linux_kernel:4.5:-:*:*:*:*:*:*
  • OR cpe:/o:linux:linux_kernel:4.5:rc1:*:*:*:*:*:*
  • OR cpe:/o:linux:linux_kernel:4.5:rc2:*:*:*:*:*:*
  • OR cpe:/o:linux:linux_kernel:4.5:rc3:*:*:*:*:*:*
  • OR cpe:/o:linux:linux_kernel:4.5:rc4:*:*:*:*:*:*

    • Configuration 2:
  • cpe:/o:redhat:enterprise_linux:7.0:*:*:*:*:*:*:*

    • * Denotes that component is vulnerable
    Oval Definitions
    Definition IDClassTitleLast Modified
    oval:org.opensuse.security:def:40391
    P
    		Security update for the Linux Kernel (Important)
    2021-11-22
    oval:org.opensuse.security:def:44821
    P
    		Security update for the Linux Kernel (Important)
    2021-11-22
    oval:org.opensuse.security:def:41438
    P
    		Security update for the Linux Kernel (Important)
    2021-05-12
    oval:org.opensuse.security:def:45868
    P
    		Security update for the Linux Kernel (Important)
    2021-05-12
    BACK
    linux linux kernel *
    linux linux kernel 4.5 -
    linux linux kernel 4.5 rc1
    linux linux kernel 4.5 rc2
    linux linux kernel 4.5 rc3
    linux linux kernel 4.5 rc4
    redhat enterprise linux 7.0