CVE-2021-31360 Junos OS and Junos OS Evolved: Denial of Service vulnerability in local file processing
A low-privileged user can overwrite local files as root via the CLI, potentially causing system integrity issues or denial of service.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2021-31360?
CVE-2021-31360 is a high-severity vulnerability in Juniper Junos, published on 19 Oct 2021. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
An improper privilege management vulnerability in the Juniper Networks Junos OS and Junos OS Evolved command-line interpreter (CLI) allows a low-privileged user to overwrite local files as root, possibly leading to a system integrity issue or Denial of Service (DoS). Depending on the files overwritten, exploitation of this vulnerability could lead to a sustained Denial of Service (DoS) condition, requiring manual user intervention to recover. Systems are only vulnerable if jdhcpd is running, which can be confirmed via the 'show system processes' command. For example: root@host# run show system processes extensive | match dhcp 26537 root -16 0 97568K 13692K RUN 0 0:01 3.71% jdhcpd This issue affects: Juniper Networks Junos OS: All versions, including the following supported releases: 15.1 versions prior to 15.1R7-S10; 17.4 versions prior to 17.4R3-S5; 18.3 versions prior to 18.3R3-S5; 18.4 versions prior to 18.4R3-S9; 19.1 versions prior to 19.1R3-S6; 19.2 versions prior to 19.2R1-S7, 19.2R3-S3; 19.3 versions prior to 19.3R2-S6, 19.3R3-S3; 19.4 versions prior to 19.4R3-S6; 20.1 versions prior to 20.1R2-S2, 20.1R3-S1; 20.2 versions prior to 20.2R3-S2; 20.3 versions prior to 20.3R3; 20.4 versions prior to 20.4R2-S1, 20.4R3; 21.1 versions prior to 21.1R1-S1, 21.1R2. Juniper Networks Junos OS Evolved: All versions prior to 20.4R2-S3-EVO; All versions of 21.1-EVO.
Which versions are affected by CVE-2021-31360?
It affects 2 products.
Products include Juniper Junos, Juniper Junos Os Evolved.
How do I fix CVE-2021-31360?
No fix has been published for CVE-2021-31360 yet. Limit exposure of the affected software until one is available.
Is CVE-2021-31360 being exploited?
There is no known exploitation of CVE-2021-31360 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-j6cc-h7v7-4cvc.