What’s Vulnerable › Vulnerabilities

CVE-2018-20836

• Severity: high (CVSS 8.1 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 5.1% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2019-05-07 · updated 2026-06-17
• Weakness: CWE-362

Description

An issue was discovered in the Linux kernel before 4.20. There is a race condition in smp_task_timedout() and smp_task_done() in drivers/scsi/libsas/sas_expander.c, leading to a use-after-free.

Affected products

• Canonical Ubuntu Linux: 16.04
• Debian Linux: 8.0, 9.0, 10.0
• F5 Traffix SDC: 5.0.0, 5.1.0
• Linux kernel: before 3.16.72; from 3.17 before 3.18.140; from 3.19 before 4.4.180; from 4.5 before 4.9.175; from 4.10 before 4.14.118; from 4.15 before 4.19.42 — fixed in 3.16.72, 3.18.140, 4.14.118, 4.19.42, 4.4.180, 4.9.175
• Active IQ Unified Manager for VMware vSphere, Linux, and Microsoft Windows: from 9.5
• NetApp Hci Compute Node: all versions
• NetApp Snapprotect: all versions
• NetApp Solidfire & Hci Management Node: all versions
• NetApp Solidfire & Hci Storage Node: all versions
• NetApp Storage Replication Adapter For Clustered Data Ontap: all versions
• NetApp Vasa Provider For Clustered Data Ontap: from 7.2
• NetApp Virtual Storage Console: from 7.2
• openSUSE Leap: 15.0, 15.1

How to fix

Upgrade to a fixed version: Linux kernel 3.16.72, 3.18.140, 4.14.118, 4.19.42. Check the vendor advisory for mitigations.

References

• http://lists.opensuse.org/opensuse-security-announce/2019-07/msg00014.html
• http://lists.opensuse.org/opensuse-security-announce/2019-07/msg00025.html
• http://www.securityfocus.com/bid/108196
• https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=b90cd6f2b905905fb42671009dc0e27c310a16ae
• https://github.com/torvalds/linux/commit/b90cd6f2b905905fb42671009dc0e27c310a16ae
• https://lists.debian.org/debian-lts-announce/2019/08/msg00016.html
• https://lists.debian.org/debian-lts-announce/2019/08/msg00017.html
• https://seclists.org/bugtraq/2019/Aug/13
• https://seclists.org/bugtraq/2019/Aug/18
• https://security.netapp.com/advisory/ntap-20190719-0003/
• https://support.f5.com/csp/article/K11225249
• https://usn.ubuntu.com/4076-1/

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