Exploited vulnerability · CISA KEV

Is CVE-2020-1631 exploited? Yes: in CISA KEV since 25 Mar 2022

Gociux · Juniper Junos OS · data: CISA KEV, CVE record, FIRST EPSS

Yes. CVE-2020-1631, Juniper Junos OS Path Traversal Vulnerability, is being exploited in the wild. CISA added it to its Known Exploited Vulnerabilities catalog on 25 Mar 2022, 690 days after it was published. It affects Juniper Junos OS, an internet-facing product of the kind attackers use for initial access. If you run it, CISA's required action is: Apply updates per vendor instructions.

exploitedYesCISA KEV · 25 Mar 2022

ransomwareNot knownno confirmed use

EPSStop 10%more likely than most to be exploited

severity8.8CVSS 3.1 · high

US federal due15 Apr 2022BOD 22-01 deadline

What it is

A path traversal vulnerability in the HTTP/HTTPS service used by J-Web, Web Authentication, Dynamic-VPN (DVPN), Firewall Authentication Pass-Through with Web-Redirect, and Zero Touch Provisioning (ZTP) allows an unauthenticated attacker to perform remote code execution.

Vendor	Juniper (8 exploited CVEs in KEV)
Product	Junos OS
Vulnerability	Juniper Junos OS Path Traversal Vulnerability
Weakness	CWE-22, CWE-73
Published	4 May 2020
Added to KEV	25 Mar 2022
Reported by (CNA)	juniper

What to do

Check whether you run it. Look for Junos OS in your asset inventory, including appliances and cloud images. Stack check lists every exploited Juniper CVE at once.
Apply the fix. Apply updates per vendor instructions.
If you can't patch today, take the affected service off the internet or restrict who can reach it, and check its logs for signs of compromise since 4 May 2020.
Get told next time. Email alerts when CISA adds a CVE for Juniper.

Other exploited CVEs in Junos OS

CVE-2025-21590: Juniper Junos OS Improper Isolation or Compartmentalization Vulnerability (13 Mar 2025)
CVE-2023-36844: Juniper Junos OS EX Series PHP External Variable Modification Vulnerability (13 Nov 2023)
CVE-2023-36845: Juniper Junos OS EX Series and SRX Series PHP External Variable Modification Vulnerability (13 Nov 2023)
CVE-2023-36846: Juniper Junos OS SRX Series Missing Authentication for Critical Function Vulnerability (13 Nov 2023)
CVE-2023-36847: Juniper Junos OS EX Series Missing Authentication for Critical Function Vulnerability (13 Nov 2023)
CVE-2023-36851: Juniper Junos OS SRX Series Missing Authentication for Critical Function Vulnerability (13 Nov 2023)

References

nvd.nist.gov/vuln/detail/CVE-2020-1631

Questions

Is CVE-2020-1631 being exploited?

Yes. CISA added CVE-2020-1631 to the Known Exploited Vulnerabilities catalog on 25 Mar 2022, which means there is reliable evidence of exploitation in the wild.

Is CVE-2020-1631 used in ransomware attacks?

CISA does not list known ransomware use for it. That can change, and exploitation alone is reason to fix it first.

How do I fix CVE-2020-1631?

Apply updates per vendor instructions. Check Juniper's advisory for the fixed versions, and if you can't patch quickly, restrict access to the affected Junos OS and watch it for signs of compromise.

Sources: CISA KEV (exploitation, ransomware use, required action, due date), the CVE record (publication date, CVSS, CNA), NVD and FIRST EPSS (live score). More: all KEV additions in March 2022 · Juniper scorecard · act-now radar.

Running Juniper in a regulated environment?

We check exposure across your estate, patch or mitigate with your team, and set up detection for what attackers do after exploiting it.

Get in touch →