Race condition in Junos OS - CVE-2021-0247
Published: April 16, 2021
Vulnerability identifier: #VU52284
CSH Severity: Medium
CVSS v4: 6.3 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N]
CVE-ID: CVE-2021-0247
CWE-ID: CWE-362
Exploitation vector: Remote access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a remote attacker to bypass implemented security restrictions.
The vulnerability exists due to a race condition in the firewall process (dfwd). A remote attacker can bypass the firewall rule sets applied to the input loopback filter on any interfaces of a device.
Affected software
Junos OS
How to mitigate CVE-2021-0247
Install updates from vendor's website.
Junos OS - addressed in versions 14.1X53-D53, 15.1X53-D593, 15.1R7-S6, 16.1R7-S7, 16.2R2-S11, 16.2R3, 17.1R2-S11, 17.1R3-S2, 17.2R1-S9, 17.2R3-S3, 17.3R2-S5, 17.3R3-S7, 17.4R2-S9, 17.4R3, 18.1R3-S9, 18.2R2-S6, 18.2R3-S3, 18.3R1-S7, 18.3R2-S3, 18.3R3-S1, 18.4R1-S5, 18.4R2-S3, 18.4R3, 19.1R1-S4, 19.1R2-S1, 19.1R3, 19.2R1-S3, 19.2R2, 19.3R1