CVE-2018-20856 json
An issue was discovered in the Linux kernel before 4.18.7.
published 2019-07-26 7 y ago modified 2026-06-17 4 mo ago also EUVD-2018-13396
- cvss
- 7.8
- version 3.0, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.7%
- EPSS 0.7% chance of exploitation in 30 days, percentile 53%
- public exploits
- 0
- none known
Summary
An issue was discovered in the Linux kernel before 4.18.7. In block/blk-core.c, there is an __blk_drain_queue() use-after-free because a certain error case is mishandled.
Patch / fix
- linux linux_kernel 4.18.7
- linux Debian 14, Debian 13, Debian 12 4.18.8-1
debian advisories DEBIAN-CVE-2018-20856
- linux Ubuntu 16.04 LTS 4.4.0-161.189
- linux Ubuntu 18.04 LTS 4.15.0-58.64
- linux-aws Ubuntu 16.04 LTS 4.4.0-1092.103
- linux-aws Ubuntu 18.04 LTS 4.15.0-1047.49
- linux-gcp Ubuntu 16.04 LTS 4.15.0-1040.42~16.04.1
- linux-gcp Ubuntu 18.04 LTS 4.15.0-1040.42
- linux-hwe Ubuntu 16.04 LTS 4.15.0-58.64~16.04.1
- linux-kvm Ubuntu 16.04 LTS 4.4.0-1056.63
ubuntu advisories UBUNTU-CVE-2018-20856
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-alt RHEL 7 4.14.0-115.14.1.el7a
- perf RHEL 7 4.14.0-115.14.1.el7a
- kernel RHEL 7 4.14.0-115.14.1.el7a
- python-perf RHEL 7 4.14.0-115.14.1.el7a
- kernel-tools RHEL 7 4.14.0-115.14.1.el7a
- kernel-tools-libs RHEL 7 4.14.0-115.14.1.el7a
- kernel-bootwrapper RHEL 7 4.14.0-115.14.1.el7a
- kernel-abi-whitelists RHEL 7 4.14.0-115.14.1.el7a
red hat advisories RHSA-2020:0103RHSA-2019:3217RHSA-2019:3055RHSA-2019:3076RHSA-2019:3089RHSA-2020:0543
- kernel-syms SLES for SAP 12 SP2, SLES 12 SP2-LTSS, SLES 12 SP2-BCL +2 more 4.4.121-92.120.1
- kernel-source SLES for SAP 12 SP2, SLES 12 SP2-LTSS, SLES 12 SP2-BCL +2 more 4.4.121-92.120.1
- kernel-default SLES for SAP 12 SP2, SLES 12 SP2-LTSS, SLES 12 SP2-BCL +3 more 4.4.121-92.120.1
- kgraft-patch-SLE12-SP2_Update_32 SLES for SAP 12 SP2, SLES 12 SP2-LTSS, OpenStack Cloud 7 +1 more 1-3.3.1
- kernel-syms SLES for SAP 12 SP3, SLES 12 SP3-LTSS, SLES 12 SP3-BCL +4 more 4.4.180-94.103.1
- kernel-source SLES for SAP 12 SP3, SLES 12 SP3-LTSS, SLES 12 SP3-BCL +4 more 4.4.180-94.103.1
- kernel-default SLES for SAP 12 SP3, SLES 12 SP3-LTSS, SLES 12 SP3-BCL +5 more 4.4.180-94.103.1
- kgraft-patch-SLE12-SP3_Update_28 SLES for SAP 12 SP3, SLES 12 SP3-LTSS, OpenStack Cloud Crowbar 8 +3 more 1-4.3.1
suse advisories SUSE-SU-2019:3261-1SUSE-SU-2019:3260-1SUSE-SU-2019:3258-1SUSE-SU-2019:3252-1SUSE-SU-2019:3232-1SUSE-SU-2019:3228-1
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-2018-20856 updated cvss 7.0
kernel: Use-after-free in __blk_drain_queue() function in block/blk-core.c
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Red Hat Enterprise Linux Client (v. 7) perf 3.10.0-1062.4.1.el7, kernel 3.10.0-1062.4.1.el7, bpftool 3.10.0-1062.4.1.el7, python-perf 3.10.0-1062.4.1.el7, kernel-tools 3.10.0-1062.4.1.el7, kernel-tools-libs 3.10.0-1062.4.1.el7, +2 more Red Hat Enterprise Linux Client Optional (v. 7) kernel-debuginfo-common-x86_64 3.10.0-1062.4.1.el7 Red Hat Enterprise Linux ComputeNode (v. 7) perf 3.10.0-1062.4.1.el7, kernel 3.10.0-1062.4.1.el7, bpftool 3.10.0-1062.4.1.el7, python-perf 3.10.0-1062.4.1.el7, kernel-tools 3.10.0-1062.4.1.el7, kernel-tools-libs 3.10.0-1062.4.1.el7, +2 morefixed: vendor fix RHSA-2019:3055
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Red Hat Enterprise Linux ComputeNode EUS (v. 7.5) perf 3.10.0-862.48.1.el7, kernel 3.10.0-862.48.1.el7, python-perf 3.10.0-862.48.1.el7, kernel-tools 3.10.0-862.48.1.el7, kernel-tools-libs 3.10.0-862.48.1.el7, kernel-abi-whitelists 3.10.0-862.48.1.el7, +1 morefixed: vendor fix RHSA-2020:0543
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Red Hat Enterprise Linux ComputeNode EUS (v. 7.6) perf 3.10.0-957.46.1.el7, kernel 3.10.0-957.46.1.el7, bpftool 3.10.0-957.46.1.el7, python-perf 3.10.0-957.46.1.el7, kernel-tools 3.10.0-957.46.1.el7, kernel-tools-libs 3.10.0-957.46.1.el7, +2 morefixed: vendor fix RHSA-2020:0664
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Red Hat Enterprise Linux ComputeNode Optional (v. 7) kernel-debuginfo-common-x86_64 3.10.0-1062.4.1.el7fixed: vendor fix RHSA-2019:3055
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Red Hat Enterprise Linux ComputeNode Optional EUS (v. 7.5) kernel-debuginfo-common-x86_64 3.10.0-862.48.1.el7fixed: vendor fix RHSA-2020:0543
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Red Hat Enterprise Linux ComputeNode Optional EUS (v. 7.6) kernel-debuginfo-common-x86_64 3.10.0-957.46.1.el7fixed: vendor fix RHSA-2020:0664
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Red Hat Enterprise Linux for ARM and IBM Power LE (POWER9) Server (v. 7) perf 4.14.0-115.14.1.el7a, kernel 4.14.0-115.14.1.el7a, kernel-alt 4.14.0-115.14.1.el7a, python-perf 4.14.0-115.14.1.el7a, kernel-tools 4.14.0-115.14.1.el7a, kernel-tools-libs 4.14.0-115.14.1.el7a, +3 more Red Hat Enterprise Linux for ARM and IBM Power LE (POWER9) Server Optional (v. 7) kernel-debuginfo-common-ppc64le 4.14.0-115.14.1.el7afixed: vendor fix RHSA-2019:3217
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Red Hat Enterprise Linux for Real Time for NFV (v. 7) kernel-rt 3.10.0-1062.4.1.rt56.1027.el7, kernel-rt-kvm 3.10.0-1062.4.1.rt56.1027.el7, kernel-rt-trace 3.10.0-1062.4.1.rt56.1027.el7, kernel-rt-debug-kvm 3.10.0-1062.4.1.rt56.1027.el7, kernel-rt-trace-kvm 3.10.0-1062.4.1.rt56.1027.el7, kernel-rt-debuginfo-common-x86_64 3.10.0-1062.4.1.rt56.1027.el7 Red Hat Enterprise Linux Realtime (v. 7) kernel-rt 3.10.0-1062.4.1.rt56.1027.el7, kernel-rt-trace 3.10.0-1062.4.1.rt56.1027.el7, kernel-rt-debuginfo-common-x86_64 3.10.0-1062.4.1.rt56.1027.el7fixed: vendor fix RHSA-2019:3089
show 13 moreshow fewer
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Red Hat Enterprise Linux Server (v. 7) perf 3.10.0-1062.4.1.el7, kernel 3.10.0-1062.4.1.el7, bpftool 3.10.0-1062.4.1.el7, python-perf 3.10.0-1062.4.1.el7, kernel-kdump 3.10.0-1062.4.1.el7, kernel-tools 3.10.0-1062.4.1.el7, +10 morefixed: vendor fix RHSA-2019:3055
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Red Hat Enterprise Linux Server AUS (v. 7.4) perf 3.10.0-693.62.1.el7, kernel 3.10.0-693.62.1.el7, python-perf 3.10.0-693.62.1.el7, kernel-tools 3.10.0-693.62.1.el7, kernel-tools-libs 3.10.0-693.62.1.el7, kernel-abi-whitelists 3.10.0-693.62.1.el7, +1 more Red Hat Enterprise Linux Server E4S (v. 7.4) perf 3.10.0-693.62.1.el7, kernel 3.10.0-693.62.1.el7, python-perf 3.10.0-693.62.1.el7, kernel-tools 3.10.0-693.62.1.el7, kernel-tools-libs 3.10.0-693.62.1.el7, kernel-bootwrapper 3.10.0-693.62.1.el7, +3 morefixed: vendor fix RHSA-2020:0103
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Red Hat Enterprise Linux Server EUS (v. 7.5) perf 3.10.0-862.48.1.el7, kernel 3.10.0-862.48.1.el7, python-perf 3.10.0-862.48.1.el7, kernel-kdump 3.10.0-862.48.1.el7, kernel-tools 3.10.0-862.48.1.el7, kernel-tools-libs 3.10.0-862.48.1.el7, +6 morefixed: vendor fix RHSA-2020:0543
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Red Hat Enterprise Linux Server EUS (v. 7.6) perf 3.10.0-957.46.1.el7, kernel 3.10.0-957.46.1.el7, bpftool 3.10.0-957.46.1.el7, python-perf 3.10.0-957.46.1.el7, kernel-kdump 3.10.0-957.46.1.el7, kernel-tools 3.10.0-957.46.1.el7, +14 morefixed: vendor fix RHSA-2020:0664
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Red Hat Enterprise Linux Server Optional (v. 7) kernel-debuginfo-common-ppc64 3.10.0-1062.4.1.el7, kernel-debuginfo-common-x86_64 3.10.0-1062.4.1.el7, kernel-debuginfo-common-ppc64le 3.10.0-1062.4.1.el7fixed: vendor fix RHSA-2019:3055
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Red Hat Enterprise Linux Server Optional AUS (v. 7.4) kernel-debuginfo-common-x86_64 3.10.0-693.62.1.el7 Red Hat Enterprise Linux Server Optional E4S (v. 7.4) kernel-debuginfo-common-x86_64 3.10.0-693.62.1.el7, kernel-debuginfo-common-ppc64le 3.10.0-693.62.1.el7fixed: vendor fix RHSA-2020:0103
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Red Hat Enterprise Linux Server Optional EUS (v. 7.5) kernel-debuginfo-common-ppc64 3.10.0-862.48.1.el7, kernel-debuginfo-common-x86_64 3.10.0-862.48.1.el7, kernel-debuginfo-common-ppc64le 3.10.0-862.48.1.el7fixed: vendor fix RHSA-2020:0543
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Red Hat Enterprise Linux Server Optional EUS (v. 7.6) kernel-debuginfo-common-ppc64 3.10.0-957.46.1.el7, kernel-debuginfo-common-x86_64 3.10.0-957.46.1.el7, kernel-debuginfo-common-ppc64le 3.10.0-957.46.1.el7fixed: vendor fix RHSA-2020:0664
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Red Hat Enterprise Linux Server Optional TUS (v. 7.4) kernel-debuginfo-common-x86_64 3.10.0-693.62.1.el7 Red Hat Enterprise Linux Server TUS (v. 7.4) perf 3.10.0-693.62.1.el7, kernel 3.10.0-693.62.1.el7, python-perf 3.10.0-693.62.1.el7, kernel-tools 3.10.0-693.62.1.el7, kernel-tools-libs 3.10.0-693.62.1.el7, kernel-abi-whitelists 3.10.0-693.62.1.el7, +1 morefixed: vendor fix RHSA-2020:0103
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Red Hat Enterprise Linux Workstation (v. 7) perf 3.10.0-1062.4.1.el7, kernel 3.10.0-1062.4.1.el7, bpftool 3.10.0-1062.4.1.el7, python-perf 3.10.0-1062.4.1.el7, kernel-tools 3.10.0-1062.4.1.el7, kernel-tools-libs 3.10.0-1062.4.1.el7, +2 more Red Hat Enterprise Linux Workstation Optional (v. 7) kernel-debuginfo-common-x86_64 3.10.0-1062.4.1.el7fixed: vendor fix RHSA-2019:3055
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Red Hat MRG Realtime for RHEL 6 Server v.2 kernel-rt 3.10.0-693.62.1.rt56.659.el6rt, kernel-rt-trace 3.10.0-693.62.1.rt56.659.el6rt, kernel-rt-vanilla 3.10.0-693.62.1.rt56.659.el6rt, kernel-rt-firmware 3.10.0-693.62.1.rt56.659.el6rt, kernel-rt-debuginfo-common-x86_64 3.10.0-693.62.1.rt56.659.el6rtfixed: vendor fix RHSA-2020:0100
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Red Hat Virtualization 4.2 Hypervisor for RHEL 7.6 EUS perf 3.10.0-957.46.1.el7, python-perf 3.10.0-957.46.1.el7fixed: vendor fix RHSA-2020:0664
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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 Linux 8 perf, kernel, bpftool, kernel-rt, kernel-core, kernel-tools, +29 morenot 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
0.71% chance of exploitation in the next 30 days, higher than 53% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| NVD | 3.0 | 7.8 | CVSS:3.0/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| NVD | 2.0 | 4.6 | AV:L/AC:L/Au:N/C:P/I:P/A:P |
Classification
- Weakness
-
- CWE-416 Use After Free
- Technology feeds
References
-
github.com
/torvalds/linux/commit/54648cf1ec2d7f4b6a71767799c45676a138ca24
patch, third-party-advisory
-
git.kernel.org
/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=54648cf1ec2d7f4b6a71767799c45676a138ca24
mailing-list, patch, vendor-advisory
-
usn.ubuntu.com
/4094-1/
vendor-advisory
-
debian.org
/security/2019/dsa-4497
vendor-advisory
-
usn.ubuntu.com
/4116-1/
vendor-advisory
-
usn.ubuntu.com
/4118-1/
vendor-advisory
-
access.redhat.com
/errata/RHSA-2019:3076
vendor-advisory
-
access.redhat.com
/errata/RHSA-2019:3055
vendor-advisory
-
access.redhat.com
/errata/RHSA-2019:3089
vendor-advisory
-
access.redhat.com
/errata/RHSA-2019:3217
vendor-advisory
-
access.redhat.com
/errata/RHSA-2020:0100
vendor-advisory
-
access.redhat.com
/errata/RHSA-2020:0103
vendor-advisory
-
access.redhat.com
/errata/RHSA-2020:0543
vendor-advisory
-
access.redhat.com
/errata/RHSA-2020:0664
vendor-advisory
-
access.redhat.com
/errata/RHSA-2020:0698
vendor-advisory
-
cdn.kernel.org
/pub/linux/kernel/v4.x/ChangeLog-4.18.7
mailing-list, release-notes, vendor-advisory
-
seclists.org
/bugtraq/2019/Aug/18
mailing-list
-
seclists.org
/bugtraq/2019/Aug/26
mailing-list
-
lists.debian.org
/debian-lts-announce/2019/08/msg00017.html
mailing-list
- packetstormsecurity.com /files/154059/Slackware-Security-Advisory-Slackware-14.2-kernel-Updates.html
- security.netapp.com /advisory/ntap-20190905-0002/
- packetstormsecurity.com /files/154408/Kernel-Live-Patch-Security-Notice-LSN-0055-1.html
- support.f5.com /csp/article/K14673240?utm_source=f5support&%3Butm_medium=RSS
- packetstormsecurity.com /files/154951/Kernel-Live-Patch-Security-Notice-LSN-0058-1.html
Sources
- CVE List CVE-2018-20856
- NVD CVE-2018-20856
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.