CVE-2020-1667 Junos OS: MX Series: Services card might restart due to a race condition when DNS filtering is enabled.
Attackers can trigger a race condition in DNS filtering to crash services, causing a denial of service and bypassing security filters.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2020-1667?
CVE-2020-1667 is a high-severity vulnerability in Juniper Junos, published on 16 Oct 2020. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
When DNS filtering is enabled on Juniper Networks Junos MX Series with one of the following cards MS-PIC, MS-MIC or MS-MPC, an incoming stream of packets processed by the Multiservices PIC Management Daemon (mspmand) process might be bypassed due to a race condition. Due to this vulnerability, mspmand process, responsible for managing "URL Filtering service", can crash, causing the Services PIC to restart. While the Services PIC is restarting, all PIC services including DNS filtering service (DNS sink holing) will be bypassed until the Services PIC completes its boot process. This issue affects Juniper Networks Junos OS: 17.3 versions prior to 17.3R3-S8; 18.3 versions prior to 18.3R3-S1; 18.4 versions prior to 18.4R3; 19.1 versions prior to 19.1R3; 19.2 versions prior to 19.2R2; 19.3 versions prior to 19.3R3. This issue does not affect Juniper Networks Junos OS 17.4, 18.1, and 18.2.
Weakness: CWE-362
Which versions are affected by CVE-2020-1667?
It affects 1 product.
Products include Juniper Junos.
How do I fix CVE-2020-1667?
No fix has been published for CVE-2020-1667 yet. Limit exposure of the affected software until one is available.
Is CVE-2020-1667 being exploited?
There is no known exploitation of CVE-2020-1667 in the wild and no public exploit code.
Other vulnerabilities in Juniper Junos
- CVE-2023-36845 Juniper Junos OS EX Series and SRX Series PHP External Variable Modification
- CVE-2020-1631 Juniper Junos OS Path Traversal
- CVE-2025-21590 Juniper Junos OS Improper Isolation or Compartmentalization
- CVE-2023-36851 Juniper Junos OS SRX Series Missing Authentication for Critical Function
- CVE-2023-36844 Juniper Junos OS EX Series PHP External Variable Modification
Sources
Also known as GHSA-752f-63g3-9w4c.