PT-2019-4660 · Linux+1 · Linux Kernel+1

Yi Ren · Published 2019-09-20 · Updated 2021-05-28 · CVE-2019-20422

Positive Technologies (AI Summary)

CVSS v3.1

5.5

Medium

Base vector

AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Name of the Vulnerable Software and Affected Versions Linux kernel versions prior to 5.3.4

Description The issue is related to the fib6 rule lookup function in the Linux kernel, which mishandles the RT6 LOOKUP F DST NOREF flag in a reference-count decision. This can lead to a crash, as identified by syzkaller. The vulnerability is also associated with errors in handling exceptional states, which can be exploited to cause a denial of service.

Recommendations For Linux kernel versions prior to 5.3.4, update to version 5.3.4 or later to resolve the issue. As a temporary workaround, consider restricting access to the fib6 rule lookup function to minimize the risk of exploitation.

Fix

Improper Handling of Exceptional Conditions

Weakness Enumeration

CWE-755

Related Identifiers

ALT-PU-2019-2838

ALT-PU-2019-2845

ALT-PU-2019-2891

ALT-PU-2020-1198

ALT-PU-2020-1501

ALT-PU-2020-1714

ALT-PU-2020-2410

ALT-PU-2020-2433

ALT-PU-2021-1870

BDU:2020-00849

CVE-2019-20422

Affected Products

Alt Linux

Linux Kernel

References · 13

• https://github.com/torvalds/linux/commit/7b09c2d052db4b4ad0b27b97918b46a7746966fa · Patch
• https://bdu.fstec.ru/vul/2020-00849 · Security Note
• https://ubuntu.com/security/CVE-2019-20422 · Vendor Advisory
• https://osv.dev/vulnerability/CVE-2019-20422 · Vendor Advisory
• https://cdn.kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.3.4 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2019-20422 · Security Note
• https://cve.org/CVERecord?id=CVE-2019-20422 · Security Note
• https://osv.dev/vulnerability/UBUNTU-CVE-2019-20422 · Vendor Advisory
• https://git.kernel.org/linus/7b09c2d052db4b4ad0b27b97918b46a7746966fa · Note
• https://t.me/cvenotify/428 · Telegram Post
• https://security.netapp.com/advisory/ntap-20200313-0003 · Note
• https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2019-20422 · Note
• https://kernel.org/pub/linux/kernel/v5.x/ChangeLog-5.3.4 · Note