A flaw was found in the Linux kernel's implementation of biovecs in versions before 5.9-rc7.

published 2020-10-06 6 y ago modified 2026-06-17 4 mo ago also EUVD-2020-18307

cvss: 5.5; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 0.4%; EPSS 0.4% chance of exploitation in 30 days, percentile 32%
public exploits: 0; none known

A flaw was found in the Linux kernel's implementation of biovecs in versions before 5.9-rc7. A zero-length biovec request issued by the block subsystem could cause the kernel to enter an infinite loop, causing a denial of service. This flaw allows a local attacker with basic privileges to issue requests to a block device, resulting in a denial of service. The highest threat from this vulnerability is to system availability.

Patch / fix

distros 5 links 2

debian ubuntu red hat suse opensuse

linux Debian 14, Debian 13, Debian 12 5.8.10-1

debian advisories DEBIAN-CVE-2020-25641

linux Ubuntu 18.04 LTS 4.15.0-126.129
linux Ubuntu 20.04 LTS 5.4.0-51.56
linux-aws Ubuntu 18.04 LTS 4.15.0-1088.93
linux-aws Ubuntu 20.04 LTS 5.4.0-1028.29
linux-gcp Ubuntu 16.04 LTS 4.15.0-1088.101~16.04.1
linux-gcp Ubuntu 20.04 LTS 5.4.0-1028.29
linux-hwe Ubuntu 16.04 LTS 4.15.0-126.129~16.04.1
linux-kvm Ubuntu 18.04 LTS 4.15.0-1079.81

ubuntu advisories UBUNTU-CVE-2020-25641

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

kernel RHEL 8 4.18.0-240.el8
perf RHEL 8 4.18.0-240.el8
bpftool RHEL 8 4.18.0-240.el8
kernel-core RHEL 8 4.18.0-240.el8
kernel-tools RHEL 8 4.18.0-240.el8
python3-perf RHEL 8 4.18.0-240.el8
kernel-modules RHEL 8 4.18.0-240.el8
kernel-zfcpdump RHEL 8 4.18.0-240.el8

red hat advisories RHSA-2020:4431 RHSA-2020:4609 RHSA-2021:0136 RHSA-2021:0073 RHSA-2020:5374 RHSA-2020:5079

kernel-syms SLES for SAP 12 SP4, SLES 12 SP4-LTSS, OpenStack Cloud Crowbar 9 +1 more 4.12.14-95.65.1
kernel-source SLES for SAP 12 SP4, SLES 12 SP4-LTSS, OpenStack Cloud Crowbar 9 +1 more 4.12.14-95.65.1
kernel-default SLES for SAP 12 SP4, SLES 12 SP4-LTSS, SLE Live Patching 12 SP4 +3 more 4.12.14-95.65.1
kernel-syms SLES for SAP 15, SLES 15-LTSS, SLE High Performance Computing 15-LTSS +1 more 4.12.14-150.63.1
kernel-source SLES for SAP 15, SLES 15-LTSS, SLE High Performance Computing 15-LTSS +1 more 4.12.14-150.63.1
kernel-default SLES for SAP 15, SLES 15-LTSS, SLE Live Patching 15 +3 more 4.12.14-150.63.1
kernel-vanilla SLES for SAP 15, SLES 15-LTSS, SLE High Performance Computing 15-LTSS +1 more 4.12.14-150.63.1
kernel-obs-build SLES for SAP 15, SLES 15-LTSS, SLE High Performance Computing 15-LTSS +1 more 4.12.14-150.63.1

suse advisories SUSE-SU-2020:3544-1 SUSE-SU-2020:3532-1 SUSE-SU-2020:3503-1 SUSE-SU-2020:3491-1 SUSE-SU-2020:3230-1 SUSE-SU-2020:3014-1

kernel-rt openSUSE Leap 15.2 5.3.18-lp152.3.5.1
kernel-syms-rt openSUSE Leap 15.2 5.3.18-lp152.3.5.1
kernel-rt_debug openSUSE Leap 15.2 5.3.18-lp152.3.5.1
kernel-source-rt openSUSE Leap 15.2 5.3.18-lp152.3.5.1
kernel-default-base openSUSE Leap 15.2 5.3.18-lp152.50.1.lp152.8.10.1
kernel-syms openSUSE Leap 15.2 5.3.18-lp152.47.1
kernel-obs-qa openSUSE Leap 15.2 5.3.18-lp152.47.1
kernel-source openSUSE Leap 15.2 5.3.18-lp152.47.2

opensuse advisories openSUSE-SU-2021:0242-1 openSUSE-SU-2020:2112-1 openSUSE-SU-2020:1698-1 openSUSE-SU-2020:1655-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2020-25641 updated 2026-11-05 cvss 5.5

kernel: soft-lockups in iov_iter_copy_from_user_atomic() could result in DoS

Red Hat Enterprise Linux 5 kernel Red Hat Enterprise Linux 6 perf, kernel, python-perf, kernel-kdump, kernel-firmware, kernel-bootwrapper, +1 more Red Hat Enterprise MRG 2 kernel
affected: workaround, no fix planned “Out of support scope”
Red Hat CodeReady Linux Builder (v. 8) kernel-debuginfo-common-x86_64 4.18.0-240.el8, kernel-debuginfo-common-aarch64 4.18.0-240.el8, kernel-debuginfo-common-ppc64le 4.18.0-240.el8
fixed: vendor fix RHSA-2020:4431
Red Hat CodeReady Linux Builder EUS (v. 8.1) kernel-debuginfo-common-x86_64 4.18.0-147.34.1.el8_1, kernel-debuginfo-common-aarch64 4.18.0-147.34.1.el8_1, kernel-debuginfo-common-ppc64le 4.18.0-147.34.1.el8_1
fixed: vendor fix RHSA-2020:5374
Red Hat CodeReady Linux Builder EUS (v. 8.2) kernel-debuginfo-common-x86_64 4.18.0-193.40.1.el8_2, kernel-debuginfo-common-aarch64 4.18.0-193.40.1.el8_2, kernel-debuginfo-common-ppc64le 4.18.0-193.40.1.el8_2
fixed: vendor fix RHSA-2021:0073
Red Hat Enterprise Linux BaseOS (v. 8) perf 4.18.0-240.el8, kernel 4.18.0-240.el8, bpftool 4.18.0-240.el8, kernel-core 4.18.0-240.el8, kernel-tools 4.18.0-240.el8, python3-perf 4.18.0-240.el8, +15 more
fixed: vendor fix RHSA-2020:4431
Red Hat Enterprise Linux BaseOS EUS (v. 8.1) perf 4.18.0-147.34.1.el8_1, kernel 4.18.0-147.34.1.el8_1, bpftool 4.18.0-147.34.1.el8_1, kernel-core 4.18.0-147.34.1.el8_1, kernel-tools 4.18.0-147.34.1.el8_1, python3-perf 4.18.0-147.34.1.el8_1, +15 more
fixed: vendor fix RHSA-2020:5374
Red Hat Enterprise Linux BaseOS EUS (v. 8.2) perf 4.18.0-193.40.1.el8_2, kernel 4.18.0-193.40.1.el8_2, bpftool 4.18.0-193.40.1.el8_2, kernel-core 4.18.0-193.40.1.el8_2, kernel-tools 4.18.0-193.40.1.el8_2, python3-perf 4.18.0-193.40.1.el8_2, +15 more
fixed: vendor fix RHSA-2021:0073
Red Hat Enterprise Linux for ARM and IBM Power LE (POWER9) Server (v. 7) perf 4.14.0-115.33.1.el7a, kernel 4.14.0-115.33.1.el7a, kernel-alt 4.14.0-115.33.1.el7a, python-perf 4.14.0-115.33.1.el7a, kernel-tools 4.14.0-115.33.1.el7a, kernel-tools-libs 4.14.0-115.33.1.el7a, +3 more Red Hat Enterprise Linux for ARM and IBM Power LE (POWER9) Server Optional (v. 7) kernel-debuginfo-common-ppc64le 4.14.0-115.33.1.el7a
fixed: vendor fix RHSA-2020:5079

show 5 more

Red Hat Enterprise Linux Real Time (v. 8) kernel-rt 4.18.0-240.rt7.54.el8, kernel-rt-core 4.18.0-240.rt7.54.el8, kernel-rt-modules 4.18.0-240.rt7.54.el8, kernel-rt-debug-core 4.18.0-240.rt7.54.el8, kernel-rt-debug-modules 4.18.0-240.rt7.54.el8, kernel-rt-modules-extra 4.18.0-240.rt7.54.el8, +2 more
fixed: vendor fix RHSA-2020:4609
Red Hat Enterprise Linux Real Time EUS (v. 8.2) kernel-rt 4.18.0-193.40.1.rt13.90.el8_2, kernel-rt-core 4.18.0-193.40.1.rt13.90.el8_2, kernel-rt-modules 4.18.0-193.40.1.rt13.90.el8_2, kernel-rt-debug-core 4.18.0-193.40.1.rt13.90.el8_2, kernel-rt-debug-modules 4.18.0-193.40.1.rt13.90.el8_2, kernel-rt-modules-extra 4.18.0-193.40.1.rt13.90.el8_2, +2 more
fixed: vendor fix RHSA-2021:0136
Red Hat Enterprise Linux Real Time for NFV (v. 8) kernel-rt 4.18.0-240.rt7.54.el8, kernel-rt-kvm 4.18.0-240.rt7.54.el8, kernel-rt-core 4.18.0-240.rt7.54.el8, kernel-rt-modules 4.18.0-240.rt7.54.el8, kernel-rt-debug-kvm 4.18.0-240.rt7.54.el8, kernel-rt-debug-core 4.18.0-240.rt7.54.el8, +4 more
fixed: vendor fix RHSA-2020:4609
Red Hat Enterprise Linux Real Time for NFV EUS (v. 8.2) kernel-rt 4.18.0-193.40.1.rt13.90.el8_2, kernel-rt-kvm 4.18.0-193.40.1.rt13.90.el8_2, kernel-rt-core 4.18.0-193.40.1.rt13.90.el8_2, kernel-rt-modules 4.18.0-193.40.1.rt13.90.el8_2, kernel-rt-debug-kvm 4.18.0-193.40.1.rt13.90.el8_2, kernel-rt-debug-core 4.18.0-193.40.1.rt13.90.el8_2, +4 more
fixed: vendor fix RHSA-2021:0136
Red Hat Enterprise Linux 7 perf, kernel, bpftool, kernel-rt, python-perf, kernel-kdump, +8 more Red Hat Enterprise Linux BaseOS EUS (v. 8.1) kernel-doc 4.18.0-147.34.1.el8_1, kernel-headers 4.18.0-147.34.1.el8_1, kernel-cross-headers 4.18.0-147.34.1.el8_1 Red Hat Enterprise Linux BaseOS EUS (v. 8.2) kernel-headers 4.18.0-193.40.1.el8_2 Red Hat Enterprise Linux for ARM and IBM Power LE (POWER9) Server (v. 7) kernel-headers 4.14.0-115.33.1.el7a
not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

0.39% chance of exploitation in the next 30 days, higher than 32% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
NVD	3.1	5.5	CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
NVD	2.0	4.9	AV:L/AC:L/Au:N/C:N/I:N/A:C

Affected products

n/a kernel

Classification

Weakness

CWE-835 Loop with Unreachable Exit Condition

Technology feeds

Linux kernel rss critical rss

References

git.kernel.org /pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=7e24969022cbd61ddc586f14824fc205661bb124
mailing-list, patch, vendor-advisory
bugzilla.redhat.com /show_bug.cgi?id=1881424
issue-tracking, patch, third-party-advisory
lists.opensuse.org /opensuse-security-announce/2020-10/msg00021.html
vendor-advisory, mailing-list, third-party-advisory
usn.ubuntu.com /4576-1/
vendor-advisory, third-party-advisory
lists.opensuse.org /opensuse-security-announce/2020-10/msg00042.html
vendor-advisory, mailing-list, third-party-advisory
kernel.org /doc/html/latest/block/biovecs.html
vendor-advisory
openwall.com /lists/oss-security/2020/10/06/9
mailing-list, third-party-advisory
lists.debian.org /debian-lts-announce/2020/10/msg00032.html
mailing-list, third-party-advisory
lists.debian.org /debian-lts-announce/2020/10/msg00034.html
mailing-list, third-party-advisory

Sources

CVE List CVE-2020-25641
NVD CVE-2020-25641

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary