Race condition in drivers/tty/n_hdlc.c in the Linux kernel through 4.10.1 allows local users to gain privileges or cause a denial of servic…

published 2017-03-07 9 y ago modified 2026-06-17 4 mo ago also EUVD-2017-11797

cvss: 7.0; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 1.0%; EPSS 1.0% chance of exploitation in 30 days, percentile 63%
public exploits: 0; none known

Race condition in drivers/tty/n_hdlc.c in the Linux kernel through 4.10.1 allows local users to gain privileges or cause a denial of service (double free) by setting the HDLC line discipline.

Patch / fix

fixed in 1 distros 5 links 1

linux linux_kernel 3.2.87, 3.10.106, 3.12.72, 3.16.42, 3.18.49, 4.1.49, 4.4.54, 4.9.15, 4.10.3

debian ubuntu red hat suse arch linux

linux Debian 14, Debian 13, Debian 12 4.9.16-1

debian advisories DEBIAN-CVE-2017-2636

linux Ubuntu 14.04 LTS 3.13.0-112.159
linux Ubuntu 16.04 LTS 4.4.0-66.87
linux-aws Ubuntu 16.04 LTS 4.4.0-1007.16
linux-gke Ubuntu 16.04 LTS 4.4.0-1005.6
linux-hwe Ubuntu 16.04 LTS 4.8.0-41.44~16.04.1
linux-raspi2 Ubuntu 16.04 LTS 4.4.0-1046.53
linux-lts-xenial Ubuntu 14.04 LTS 4.4.0-66.87~14.04.1
linux-snapdragon Ubuntu 16.04 LTS 4.4.0-1050.54

ubuntu advisories UBUNTU-CVE-2017-2636

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 6 2.6.32-696.1.1.el6
perf RHEL 6 2.6.32-696.1.1.el6
python-perf RHEL 6 2.6.32-696.1.1.el6
kernel-kdump RHEL 6 2.6.32-696.1.1.el6
kernel-firmware RHEL 6 2.6.32-696.1.1.el6
kernel-bootwrapper RHEL 6 2.6.32-696.1.1.el6
kernel-abi-whitelists RHEL 6 2.6.32-696.1.1.el6
kernel-debuginfo-common-i686 RHEL 6 2.6.32-696.1.1.el6

red hat advisories RHSA-2017:1488 RHSA-2017:0892 RHSA-2017:0931 RHSA-2017:0932 RHSA-2017:0933 RHSA-2017:0986

kernel-rt SLE Real Time 11 SP4 3.0.101.rt130-69.5.1
kernel-syms-rt SLE Real Time 11 SP4 3.0.101.rt130-69.5.1
kernel-rt_trace SLE Real Time 11 SP4 3.0.101.rt130-69.5.1
kernel-source-rt SLE Real Time 11 SP4 3.0.101.rt130-69.5.1
kernel-rt SLE Real Time 12 SP2 4.4.74-7.10.1
kernel-syms-rt SLE Real Time 12 SP2 4.4.74-7.10.1
kernel-rt_debug SLE Real Time 12 SP2 4.4.74-7.10.1
kernel-source-rt SLE Real Time 12 SP2 4.4.74-7.10.1

suse advisories SUSE-SU-2025:0152-1 SUSE-SU-2017:2342-1 SUSE-SU-2017:2099-1 SUSE-SU-2017:2096-1 SUSE-SU-2017:2095-1 SUSE-SU-2017:2093-1

linux Arch Linux 4.10.2-1
linux-lts Arch Linux 4.9.14-1
linux-zen Arch Linux 4.10.2-1

arch linux advisories AVG-192 AVG-200 AVG-203

openwall.com/lists/oss-security/2017/03/07/6 advisory

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-2017-2636 updated 2026-11-04 cvss 7.8

kernel: Race condition access to n_hdlc.tbuf causes double free in n_hdlc_release()

Red Hat Enterprise Linux Client (v. 7) perf 3.10.0-514.16.1.el7, kernel 3.10.0-514.16.1.el7, python-perf 3.10.0-514.16.1.el7, kernel-tools 3.10.0-514.16.1.el7, kernel-tools-libs 3.10.0-514.16.1.el7, kernel-abi-whitelists 3.10.0-514.16.1.el7, +1 more Red Hat Enterprise Linux Client Optional (v. 7) kernel-debuginfo-common-x86_64 3.10.0-514.16.1.el7 Red Hat Enterprise Linux ComputeNode (v. 7) perf 3.10.0-514.16.1.el7, kernel 3.10.0-514.16.1.el7, python-perf 3.10.0-514.16.1.el7, kernel-tools 3.10.0-514.16.1.el7, kernel-tools-libs 3.10.0-514.16.1.el7, kernel-abi-whitelists 3.10.0-514.16.1.el7, +1 more
fixed: vendor fix RHSA-2017:0933
Red Hat Enterprise Linux ComputeNode EUS (v. 7.2) perf 3.10.0-327.53.1.el7, kernel 3.10.0-327.53.1.el7, python-perf 3.10.0-327.53.1.el7, kernel-tools 3.10.0-327.53.1.el7, kernel-tools-libs 3.10.0-327.53.1.el7, kernel-abi-whitelists 3.10.0-327.53.1.el7, +1 more
fixed: vendor fix RHSA-2017:1125
Red Hat Enterprise Linux ComputeNode Optional (v. 7) kernel-debuginfo-common-x86_64 3.10.0-514.16.1.el7
fixed: vendor fix RHSA-2017:0933
Red Hat Enterprise Linux ComputeNode Optional EUS (v. 7.2) kernel-debuginfo-common-x86_64 3.10.0-327.53.1.el7
fixed: vendor fix RHSA-2017:1125
Red Hat Enterprise Linux Desktop (v. 6) perf 2.6.32-696.1.1.el6, kernel 2.6.32-696.1.1.el6, kernel-firmware 2.6.32-696.1.1.el6, kernel-abi-whitelists 2.6.32-696.1.1.el6, kernel-debuginfo-common-i686 2.6.32-696.1.1.el6, kernel-debuginfo-common-x86_64 2.6.32-696.1.1.el6 Red Hat Enterprise Linux Desktop Optional (v. 6) python-perf 2.6.32-696.1.1.el6, kernel-debuginfo-common-i686 2.6.32-696.1.1.el6, kernel-debuginfo-common-x86_64 2.6.32-696.1.1.el6
fixed: vendor fix RHSA-2017:0892
Red Hat Enterprise Linux for Real Time for NFV (v. 7) kernel-rt 3.10.0-514.16.1.rt56.437.el7, kernel-rt-kvm 3.10.0-514.16.1.rt56.437.el7, kernel-rt-trace 3.10.0-514.16.1.rt56.437.el7, kernel-rt-debug-kvm 3.10.0-514.16.1.rt56.437.el7, kernel-rt-trace-kvm 3.10.0-514.16.1.rt56.437.el7, kernel-rt-debuginfo-common-x86_64 3.10.0-514.16.1.rt56.437.el7
fixed: vendor fix RHSA-2017:0931
Red Hat Enterprise Linux HPC Node (v. 6) perf 2.6.32-696.1.1.el6, kernel 2.6.32-696.1.1.el6, kernel-firmware 2.6.32-696.1.1.el6, kernel-abi-whitelists 2.6.32-696.1.1.el6, kernel-debuginfo-common-i686 2.6.32-696.1.1.el6, kernel-debuginfo-common-x86_64 2.6.32-696.1.1.el6
fixed: vendor fix RHSA-2017:0892
Red Hat Enterprise Linux HPC Node EUS (v. 6.7) perf 2.6.32-573.42.1.el6, kernel 2.6.32-573.42.1.el6, kernel-firmware 2.6.32-573.42.1.el6, kernel-abi-whitelists 2.6.32-573.42.1.el6, kernel-debuginfo-common-i686 2.6.32-573.42.1.el6, kernel-debuginfo-common-x86_64 2.6.32-573.42.1.el6
fixed: vendor fix RHSA-2017:1233

show 29 more

Red Hat Enterprise Linux HPC Node Optional (v. 6) python-perf 2.6.32-696.1.1.el6, kernel-debuginfo-common-x86_64 2.6.32-696.1.1.el6
fixed: vendor fix RHSA-2017:0892
Red Hat Enterprise Linux HPC Node Optional EUS (v. 6.7) python-perf 2.6.32-573.42.1.el6, kernel-debuginfo-common-x86_64 2.6.32-573.42.1.el6
fixed: vendor fix RHSA-2017:1233
Red Hat Enterprise Linux Realtime (v. 7) kernel-rt 3.10.0-514.16.1.rt56.437.el7, kernel-rt-trace 3.10.0-514.16.1.rt56.437.el7, kernel-rt-debuginfo-common-x86_64 3.10.0-514.16.1.rt56.437.el7
fixed: vendor fix RHSA-2017:0931
Red Hat Enterprise Linux Server (v. 6) perf 2.6.32-696.1.1.el6, kernel 2.6.32-696.1.1.el6, kernel-kdump 2.6.32-696.1.1.el6, kernel-firmware 2.6.32-696.1.1.el6, kernel-bootwrapper 2.6.32-696.1.1.el6, kernel-abi-whitelists 2.6.32-696.1.1.el6, +4 more
fixed: vendor fix RHSA-2017:0892
Red Hat Enterprise Linux Server (v. 7) perf 3.10.0-514.16.1.el7, kernel 3.10.0-514.16.1.el7, python-perf 3.10.0-514.16.1.el7, kernel-kdump 3.10.0-514.16.1.el7, kernel-tools 3.10.0-514.16.1.el7, kernel-tools-libs 3.10.0-514.16.1.el7, +6 more
fixed: vendor fix RHSA-2017:0933
Red Hat Enterprise Linux Server AUS (v. 6.2) perf 2.6.32-220.71.1.el6, kernel 2.6.32-220.71.1.el6, kernel-firmware 2.6.32-220.71.1.el6, kernel-debuginfo-common-x86_64 2.6.32-220.71.1.el6
fixed: vendor fix RHSA-2017:1126
Red Hat Enterprise Linux Server AUS (v. 6.4) perf 2.6.32-358.78.1.el6, kernel 2.6.32-358.78.1.el6, kernel-firmware 2.6.32-358.78.1.el6, kernel-debuginfo-common-x86_64 2.6.32-358.78.1.el6
fixed: vendor fix RHSA-2017:0986
Red Hat Enterprise Linux Server AUS (v. 6.5) perf 2.6.32-431.80.1.el6, kernel 2.6.32-431.80.1.el6, kernel-firmware 2.6.32-431.80.1.el6, kernel-abi-whitelists 2.6.32-431.80.1.el6, kernel-debuginfo-common-x86_64 2.6.32-431.80.1.el6
fixed: vendor fix RHSA-2017:1232
Red Hat Enterprise Linux Server AUS (v. 6.6) perf 2.6.32-504.60.2.el6, kernel 2.6.32-504.60.2.el6, kernel-firmware 2.6.32-504.60.2.el6, kernel-abi-whitelists 2.6.32-504.60.2.el6, kernel-debuginfo-common-x86_64 2.6.32-504.60.2.el6
fixed: vendor fix RHSA-2017:1488
Red Hat Enterprise Linux Server EUS (v. 6.7) perf 2.6.32-573.42.1.el6, kernel 2.6.32-573.42.1.el6, kernel-kdump 2.6.32-573.42.1.el6, kernel-firmware 2.6.32-573.42.1.el6, kernel-bootwrapper 2.6.32-573.42.1.el6, kernel-abi-whitelists 2.6.32-573.42.1.el6, +4 more
fixed: vendor fix RHSA-2017:1233
Red Hat Enterprise Linux Server EUS (v. 7.2) perf 3.10.0-327.53.1.el7, kernel 3.10.0-327.53.1.el7, python-perf 3.10.0-327.53.1.el7, kernel-kdump 3.10.0-327.53.1.el7, kernel-tools 3.10.0-327.53.1.el7, kernel-tools-libs 3.10.0-327.53.1.el7, +6 more
fixed: vendor fix RHSA-2017:1125
Red Hat Enterprise Linux Server Optional (v. 6) python-perf 2.6.32-696.1.1.el6, kernel-debuginfo-common-i686 2.6.32-696.1.1.el6, kernel-debuginfo-common-ppc64 2.6.32-696.1.1.el6, kernel-debuginfo-common-s390x 2.6.32-696.1.1.el6, kernel-debuginfo-common-x86_64 2.6.32-696.1.1.el6
fixed: vendor fix RHSA-2017:0892
Red Hat Enterprise Linux Server Optional (v. 7) kernel-debuginfo-common-ppc64 3.10.0-514.16.1.el7, kernel-debuginfo-common-x86_64 3.10.0-514.16.1.el7, kernel-debuginfo-common-ppc64le 3.10.0-514.16.1.el7
fixed: vendor fix RHSA-2017:0933
Red Hat Enterprise Linux Server Optional AUS (v. 6.2) kernel 2.6.32-220.71.1.el6, python-perf 2.6.32-220.71.1.el6, kernel-debuginfo-common-x86_64 2.6.32-220.71.1.el6
fixed: vendor fix RHSA-2017:1126
Red Hat Enterprise Linux Server Optional AUS (v. 6.4) kernel 2.6.32-358.78.1.el6, python-perf 2.6.32-358.78.1.el6, kernel-debuginfo-common-x86_64 2.6.32-358.78.1.el6
fixed: vendor fix RHSA-2017:0986
Red Hat Enterprise Linux Server Optional AUS (v. 6.5) kernel 2.6.32-431.80.1.el6, python-perf 2.6.32-431.80.1.el6, kernel-debuginfo-common-x86_64 2.6.32-431.80.1.el6
fixed: vendor fix RHSA-2017:1232
Red Hat Enterprise Linux Server Optional AUS (v. 6.6) python-perf 2.6.32-504.60.2.el6, kernel-debuginfo-common-x86_64 2.6.32-504.60.2.el6
fixed: vendor fix RHSA-2017:1488
Red Hat Enterprise Linux Server Optional EUS (v. 6.7) python-perf 2.6.32-573.42.1.el6, kernel-debuginfo-common-i686 2.6.32-573.42.1.el6, kernel-debuginfo-common-ppc64 2.6.32-573.42.1.el6, kernel-debuginfo-common-s390x 2.6.32-573.42.1.el6, kernel-debuginfo-common-x86_64 2.6.32-573.42.1.el6
fixed: vendor fix RHSA-2017:1233
Red Hat Enterprise Linux Server Optional EUS (v. 7.2) kernel-debuginfo-common-ppc64 3.10.0-327.53.1.el7, kernel-debuginfo-common-x86_64 3.10.0-327.53.1.el7, kernel-debuginfo-common-ppc64le 3.10.0-327.53.1.el7
fixed: vendor fix RHSA-2017:1125
Red Hat Enterprise Linux Server Optional TUS (v. 6.5) kernel 2.6.32-431.80.1.el6, python-perf 2.6.32-431.80.1.el6, kernel-debuginfo-common-x86_64 2.6.32-431.80.1.el6
fixed: vendor fix RHSA-2017:1232
Red Hat Enterprise Linux Server Optional TUS (v. 6.6) python-perf 2.6.32-504.60.2.el6, kernel-debuginfo-common-x86_64 2.6.32-504.60.2.el6
fixed: vendor fix RHSA-2017:1488
Red Hat Enterprise Linux Server TUS (v. 6.5) perf 2.6.32-431.80.1.el6, kernel 2.6.32-431.80.1.el6, kernel-firmware 2.6.32-431.80.1.el6, kernel-abi-whitelists 2.6.32-431.80.1.el6, kernel-debuginfo-common-x86_64 2.6.32-431.80.1.el6
fixed: vendor fix RHSA-2017:1232
Red Hat Enterprise Linux Server TUS (v. 6.6) perf 2.6.32-504.60.2.el6, kernel 2.6.32-504.60.2.el6, kernel-firmware 2.6.32-504.60.2.el6, kernel-abi-whitelists 2.6.32-504.60.2.el6, kernel-debuginfo-common-x86_64 2.6.32-504.60.2.el6
fixed: vendor fix RHSA-2017:1488
Red Hat Enterprise Linux Workstation (v. 6) perf 2.6.32-696.1.1.el6, kernel 2.6.32-696.1.1.el6, kernel-firmware 2.6.32-696.1.1.el6, kernel-abi-whitelists 2.6.32-696.1.1.el6, kernel-debuginfo-common-i686 2.6.32-696.1.1.el6, kernel-debuginfo-common-x86_64 2.6.32-696.1.1.el6
fixed: vendor fix RHSA-2017:0892
Red Hat Enterprise Linux Workstation (v. 7) perf 3.10.0-514.16.1.el7, kernel 3.10.0-514.16.1.el7, python-perf 3.10.0-514.16.1.el7, kernel-tools 3.10.0-514.16.1.el7, kernel-tools-libs 3.10.0-514.16.1.el7, kernel-abi-whitelists 3.10.0-514.16.1.el7, +1 more
fixed: vendor fix RHSA-2017:0933
Red Hat Enterprise Linux Workstation Optional (v. 6) python-perf 2.6.32-696.1.1.el6, kernel-debuginfo-common-i686 2.6.32-696.1.1.el6, kernel-debuginfo-common-x86_64 2.6.32-696.1.1.el6
fixed: vendor fix RHSA-2017:0892
Red Hat Enterprise Linux Workstation Optional (v. 7) kernel-debuginfo-common-x86_64 3.10.0-514.16.1.el7
fixed: vendor fix RHSA-2017:0933
Red Hat MRG Realtime for RHEL 6 Server v.2 kernel-rt 3.10.0-514.rt56.219.el6rt, kernel-rt-trace 3.10.0-514.rt56.219.el6rt, kernel-rt-vanilla 3.10.0-514.rt56.219.el6rt, kernel-rt-firmware 3.10.0-514.rt56.219.el6rt, kernel-rt-debuginfo-common-x86_64 3.10.0-514.rt56.219.el6rt
fixed: vendor fix RHSA-2017:0932
Red Hat Enterprise Linux 5 kernel
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

1.03% chance of exploitation in the next 30 days, higher than 63% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
NVD	3.1	7.0	CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
NVD	2.0	6.9	AV:L/AC:M/Au:N/C:C/I:C/A:C

Classification

Weakness

CWE-362 Concurrent Execution using Shared Resource with Improper Synchronization
CWE-415 Double Free

Technology feeds

Linux kernel rss critical rss

References

openwall.com /lists/oss-security/2017/03/07/6
mailing-list, patch, third-party-advisory
access.redhat.com /errata/RHSA-2017:0892
vendor-advisory, third-party-advisory
access.redhat.com /errata/RHSA-2017:0932
vendor-advisory, third-party-advisory
access.redhat.com /errata/RHSA-2017:1125
vendor-advisory, third-party-advisory
access.redhat.com /errata/RHSA-2017:0933
vendor-advisory, third-party-advisory
access.redhat.com /errata/RHSA-2017:1232
vendor-advisory, third-party-advisory
access.redhat.com /errata/RHSA-2017:0931
vendor-advisory, third-party-advisory
debian.org /security/2017/dsa-3804
vendor-advisory, third-party-advisory
access.redhat.com /errata/RHSA-2017:1233
vendor-advisory, third-party-advisory
access.redhat.com /errata/RHSA-2017:1488
vendor-advisory, third-party-advisory
access.redhat.com /errata/RHSA-2017:0986
vendor-advisory, third-party-advisory
access.redhat.com /errata/RHSA-2017:1126
vendor-advisory, third-party-advisory
securityfocus.com /bid/96732
vdb-entry, third-party-advisory
securitytracker.com /id/1037963
vdb-entry, third-party-advisory
bugzilla.redhat.com /show_bug.cgi?id=1428319
issue-tracking, mitigation, third-party-advisory
a13xp0p0v.github.io /2017/03/24/CVE-2017-2636.html
third-party-advisory

Sources

CVE List CVE-2017-2636
NVD CVE-2017-2636

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