Race condition in Linux kernel - CVE-2021-20261

Vulnerability identifier: #VU91489

CSH Severity: Low

CVSS v4: 7.1 [CVSS:4.0/AV:L/AC:L/AT:P/PR:H/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N]

CVE-ID: CVE-2021-20261

CWE-ID: CWE-362

Exploitation vector: Local access

Exploit availability: No public exploit available

The vulnerability allows a local privileged user to execute arbitrary code.

The vulnerability exists due to a race condition within the set_fdc(), do_format(), user_reset_fdc(), set_geometry(), get_floppy_geometry(), fd_locked_ioctl(), floppy_check_events() and floppy_revalidate() functions in drivers/block/floppy.c. A local privileged user can execute arbitrary code.

Linux kernel
SUSE Linux Enterprise Server
SUSE Linux Enterprise Debuginfo
Slackware Linux
Ubuntu
kernel-ec2-debuginfo
kernel-default-extra
kernel-xen-extra
kernel-trace-extra
kernel-ppc64-extra
kernel-pae-extra
kernel-default-debuginfo
kernel-default-debugsource
kernel-trace-debuginfo
kernel-trace-debugsource
kernel-default-devel-debuginfo
kernel-trace-devel-debuginfo
kernel-default-base
kernel-ec2-debugsource
kernel-xen-debuginfo
kernel-xen-debugsource
kernel-xen-devel-debuginfo
kernel-bigmem-debuginfo
kernel-bigmem-debugsource
kernel-ppc64-debuginfo
kernel-ppc64-debugsource
kernel-pae-debuginfo
kernel-pae-debugsource
kernel-pae-devel-debuginfo
kernel-pae-base
kernel-pae-devel
kernel-default
kernel-default-devel
kernel-source
kernel-syms
kernel-trace
kernel-trace-base
kernel-trace-devel
kernel-ec2
kernel-ec2-base
kernel-ec2-devel
kernel-xen-base
kernel-xen-devel
kernel-default-man
kernel-bigmem
kernel-bigmem-base
kernel-bigmem-devel
kernel-ppc64
kernel-ppc64-base
kernel-ppc64-devel
kernel-pae
kernel-xen
linux-image-generic-lpae-lts-xenial (Ubuntu package)
linux-image-generic-lts-xenial (Ubuntu package)
linux-image-lowlatency-lts-xenial (Ubuntu package)
linux-image-virtual-lts-xenial (Ubuntu package)
linux-image-virtual (Ubuntu package)
linux-image-powerpc64-smp (Ubuntu package)
linux-image-powerpc64-emb (Ubuntu package)
linux-image-powerpc-smp (Ubuntu package)
linux-image-generic (Ubuntu package)
linux-image-generic-lpae (Ubuntu package)
linux-image-powerpc-e500mc (Ubuntu package)
linux-image-lowlatency (Ubuntu package)
linux-image-4.4.0-208-powerpc-e500mc (Ubuntu package)
linux-image-4.4.0-208-powerpc-smp (Ubuntu package)
linux-image-4.4.0-208-powerpc64-emb (Ubuntu package)
linux-image-4.4.0-208-powerpc64-smp (Ubuntu package)
linux-image-4.4.0-208-generic-lpae (Ubuntu package)
linux-image-4.4.0-208-lowlatency (Ubuntu package)
linux-image-4.4.0-208-generic (Ubuntu package)
linux-image-aws (Ubuntu package)
linux-image-4.4.0-1090-aws (Ubuntu package)
linux-image-kvm (Ubuntu package)
linux-image-4.4.0-1091-kvm (Ubuntu package)
linux-image-4.4.0-1126-aws (Ubuntu package)
linux-image-raspi2 (Ubuntu package)
linux-image-4.4.0-1150-raspi2 (Ubuntu package)
linux-image-snapdragon (Ubuntu package)
linux-image-4.4.0-1154-snapdragon (Ubuntu package)
linux-4.4.276/kernel-generic
linux-4.4.276/kernel-huge
linux-4.4.276/kernel-modules
linux-4.4.276/kernel-headers

Install update from vendor's website.

kernel-ec2-debuginfo - update to 3.0.101-108.126.1
kernel-default-extra - update to 3.0.101-108.126.1
kernel-xen-extra - update to 3.0.101-108.126.1
kernel-trace-extra - update to 3.0.101-108.126.1
kernel-ppc64-extra - update to 3.0.101-108.126.1
kernel-pae-extra - update to 3.0.101-108.126.1
kernel-default-debuginfo - update to 3.0.101-108.126.1
kernel-default-debugsource - update to 3.0.101-108.126.1
kernel-trace-debuginfo - update to 3.0.101-108.126.1
kernel-trace-debugsource - update to 3.0.101-108.126.1
kernel-default-devel-debuginfo - update to 3.0.101-108.126.1
kernel-trace-devel-debuginfo - update to 3.0.101-108.126.1
kernel-default-base - update to 3.0.101-108.126.1
kernel-ec2-debugsource - update to 3.0.101-108.126.1
kernel-xen-debuginfo - update to 3.0.101-108.126.1
kernel-xen-debugsource - update to 3.0.101-108.126.1
kernel-xen-devel-debuginfo - update to 3.0.101-108.126.1
kernel-bigmem-debuginfo - update to 3.0.101-108.126.1
kernel-bigmem-debugsource - update to 3.0.101-108.126.1
kernel-ppc64-debuginfo - update to 3.0.101-108.126.1
kernel-ppc64-debugsource - update to 3.0.101-108.126.1
kernel-pae-debuginfo - update to 3.0.101-108.126.1
kernel-pae-debugsource - update to 3.0.101-108.126.1
kernel-pae-devel-debuginfo - update to 3.0.101-108.126.1
kernel-pae-base - update to 3.0.101-108.126.1
kernel-pae-devel - update to 3.0.101-108.126.1
kernel-default - update to 3.0.101-108.126.1
kernel-default-devel - update to 3.0.101-108.126.1
kernel-source - update to 3.0.101-108.126.1
kernel-syms - update to 3.0.101-108.126.1
kernel-trace - update to 3.0.101-108.126.1
kernel-trace-base - update to 3.0.101-108.126.1
kernel-trace-devel - update to 3.0.101-108.126.1
kernel-ec2 - update to 3.0.101-108.126.1
kernel-ec2-base - update to 3.0.101-108.126.1
kernel-ec2-devel - update to 3.0.101-108.126.1
kernel-xen-base - update to 3.0.101-108.126.1
kernel-xen-devel - update to 3.0.101-108.126.1
kernel-default-man - update to 3.0.101-108.126.1
kernel-bigmem - update to 3.0.101-108.126.1
kernel-bigmem-base - update to 3.0.101-108.126.1
kernel-bigmem-devel - update to 3.0.101-108.126.1
kernel-ppc64 - update to 3.0.101-108.126.1
kernel-ppc64-base - update to 3.0.101-108.126.1
kernel-ppc64-devel - update to 3.0.101-108.126.1
kernel-pae - update to 3.0.101-108.126.1
kernel-xen - update to 3.0.101-108.126.1
linux-image-generic-lpae-lts-xenial (Ubuntu package) - update to 4.4.0.208.181
linux-image-generic-lts-xenial (Ubuntu package) - update to 4.4.0.208.181
linux-image-lowlatency-lts-xenial (Ubuntu package) - update to 4.4.0.208.181
linux-image-virtual-lts-xenial (Ubuntu package) - update to 4.4.0.208.181
linux-image-virtual (Ubuntu package) - update to 4.4.0.208.214
linux-image-powerpc64-smp (Ubuntu package) - update to 4.4.0.208.214
linux-image-powerpc64-emb (Ubuntu package) - update to 4.4.0.208.214
linux-image-powerpc-smp (Ubuntu package) - update to 4.4.0.208.214
linux-image-generic (Ubuntu package) - update to 4.4.0.208.214
linux-image-generic-lpae (Ubuntu package) - update to 4.4.0.208.214
linux-image-powerpc-e500mc (Ubuntu package) - update to 4.4.0.208.214
linux-image-lowlatency (Ubuntu package) - update to 4.4.0.208.214
linux-image-4.4.0-208-powerpc-e500mc (Ubuntu package) - update to 4.4.0-208.240
linux-image-4.4.0-208-powerpc-smp (Ubuntu package) - update to 4.4.0-208.240
linux-image-4.4.0-208-powerpc64-emb (Ubuntu package) - update to 4.4.0-208.240
linux-image-4.4.0-208-powerpc64-smp (Ubuntu package) - update to 4.4.0-208.240
linux-image-4.4.0-208-generic-lpae (Ubuntu package) - update to 4.4.0-208.240~14.04.1
linux-image-4.4.0-208-lowlatency (Ubuntu package) - update to 4.4.0-208.240~14.04.1
linux-image-4.4.0-208-generic (Ubuntu package) - update to 4.4.0-208.240~14.04.1
linux-image-aws (Ubuntu package) - addressed in versions 4.4.0.1090.87, 4.4.0.1126.131
linux-image-4.4.0-1090-aws (Ubuntu package) - update to 4.4.0-1090.94
linux-image-kvm (Ubuntu package) - update to 4.4.0.1091.89
linux-image-4.4.0-1091-kvm (Ubuntu package) - update to 4.4.0-1091.100
linux-image-4.4.0-1126-aws (Ubuntu package) - update to 4.4.0-1126.140
linux-image-raspi2 (Ubuntu package) - update to 4.4.0.1150.150
linux-image-4.4.0-1150-raspi2 (Ubuntu package) - update to 4.4.0-1150.161
linux-image-snapdragon (Ubuntu package) - update to 4.4.0.1154.146
linux-image-4.4.0-1154-snapdragon (Ubuntu package) - update to 4.4.0-1154.164
linux-4.4.276/kernel-generic - update to 4.4.276
linux-4.4.276/kernel-huge - update to 4.4.276
linux-4.4.276/kernel-modules - update to 4.4.276
linux-4.4.276/kernel-headers - update to 4.4.276_smp

• https://bugzilla.redhat.com/show_bug.cgi?id=1932150
• https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=a0c80efe5956ccce9fe7ae5c78542578c07bc20a

• Race condition in Linux kernel block driver
• SUSE update for the Linux Kernel
• Ubuntu update for linux
• Slackware Linux update for kernel