Skip to content
Vulnerability Intelligence

CVE-2020-1631

CriticalExploitedPublic exploit

A 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 local file inclusion (LFI) or path traversal.

Published May 4, 2020 · Updated Oct 24, 2025

Key Facts

Patch immediately
  • CVE-2020-1631 is a critical-severity vulnerability (CVSS 9.8 v3.1) affecting Junos (Juniper), Junos OS.
  • It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since May 4, 2020. Public exploit code is available.
  • EPSS estimates a 4.8% probability of exploitation in the next 30 days.
  • Fixed versions are available, including Junos OS 12.3R12-S16, Junos OS 12.3X48-D101, 12.3X48-D105, Junos OS 14.1X53-D54.
  • Brandefense priority: patch immediately, because it is listed as exploited in the wild.

CVSS v3.1

9.8

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS (30-day exploit likelihood)

4.8%

Higher than 91.9% of all scored CVEs

Exploited in the wild

Yes

4 catalog listings

Public exploit code

Available

Proof-of-concept or weaponized module

Get the full CVE-2020-1631 brief as a PDF

Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.

Description

A 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 local file inclusion (LFI) or path traversal. Using this vulnerability, an attacker may be able to inject commands into the httpd.log, read files with 'world' readable permission file or obtain J-Web session tokens. In the case of command injection, as the HTTP service runs as user 'nobody', the impact of this command injection is limited. (CVSS score 5.3, vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N) In the case of reading files with 'world' readable permission, in Junos OS 19.3R1 and above, the unauthenticated attacker would be able to read the configuration file. (CVSS score 5.9, vector CVSS:3.1/ AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N) If J-Web is enabled, the attacker could gain the same level of access of anyone actively logged into J-Web. If an administrator is logged in, the attacker could gain administrator access to J-Web. (CVSS score 8.8, vector CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H) This issue only affects Juniper Networks Junos OS devices with HTTP/HTTPS services enabled. Junos OS devices with HTTP/HTTPS services disabled are not affected. If HTTP/HTTPS services are enabled, the following command will show the httpd processes: user@device> show system processes | match http 5260 - S 0:00.13 /usr/sbin/httpd-gk -N 5797 - I 0:00.10 /usr/sbin/httpd --config /jail/var/etc/httpd.conf To summarize: If HTTP/HTTPS services are disabled, there is no impact from this vulnerability. If HTTP/HTTPS services are enabled and J-Web is not in use, this vulnerability has a CVSS score of 5.9 (CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:N/A:N). If J-Web is enabled, this vulnerability has a CVSS score of 8.8 (CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H). Juniper SIRT has received a single report of this vulnerability being exploited in the wild. Out of an abundance of caution, we are notifying customers so they can take appropriate actions. Indicators of Compromise: The /var/log/httpd.log may have indicators that commands have injected or files being accessed. The device administrator can look for these indicators by searching for the string patterns "=*;*&" or "*%3b*&" in /var/log/httpd.log, using the following command: user@device> show log httpd.log | match "=*;*&|=*%3b*&" If this command returns any output, it might be an indication of malicious attempts or simply scanning activities. Rotated logs should also be reviewed, using the following command: user@device> show log httpd.log.0.gz | match "=*;*&|=*%3b*&" user@device> show log httpd.log.1.gz | match "=*;*&|=*%3b*&" Note that a skilled attacker would likely remove these entries from the local log file, thus effectively eliminating any reliable signature that the device had been attacked. This issue affects Juniper Networks Junos OS 12.3 versions prior to 12.3R12-S16; 12.3X48 versions prior to 12.3X48-D101, 12.3X48-D105; 14.1X53 versions prior to 14.1X53-D54; 15.1 versions prior to 15.1R7-S7; 15.1X49 versions prior to 15.1X49-D211, 15.1X49-D220; 16.1 versions prior to 16.1R7-S8; 17.2 versions prior to 17.2R3-S4; 17.3 versions prior to 17.3R3-S8; 17.4 versions prior to 17.4R2-S11, 17.4R3-S2; 18.1 versions prior to 18.1R3-S10; 18.2 versions prior to 18.2R2-S7, 18.2R3-S4; 18.3 versions prior to 18.3R2-S4, 18.3R3-S2; 18.4 versions prior to 18.4R1-S7, 18.4R3-S2 ; 18.4 version 18.4R2 and later versions; 19.1 versions prior to 19.1R1-S5, 19.1R3-S1; 19.1 version 19.1R2 and later versions; 19.2 versions prior to 19.2R2; 19.3 versions prior to 19.3R2-S3, 19.3R3; 19.4 versions prior to 19.4R1-S2, 19.4R2; 20.1 versions prior to 20.1R1-S1, 20.1R2.

Known-Exploited Catalog Listings

CatalogAddedRemediation dueRansomware use
CISA KEVMar 25, 2022Apr 15, 2022Not reported
Industry KEV feedMay 4, 2020Apr 15, 2022Not reported
CIRCL KEVMar 25, 2022Apr 15, 2022Not reported
ENISA EUVDMar 25, 2022n/aNot reported

Required action: Apply updates per vendor instructions.

Affected Products

278 affected entries in total
ProductAffected versionsFixed in
JunosJuniper12.3, 12.3-r1, 12.3-r10, 12.3-r10-s1, 12.3-r10-s2, 12.3-r11, 12.3-r12, 12.3-r12-s1n/a
Junos OS>= 12.312.3R12-S16

Patched Releases

Junos OS

12.3R12-S16, 12.3X48-D101, 12.3X48-D105, 14.1X53-D54, 15.1R7-S7, 15.1X49-D211, 15.1X49-D220, 16.1R7-S8, 17.2R3-S4, 17.3R3-S8, 17.4R2-S11, 17.4R3-S2, 18.1R3-S10, 18.2R2-S7, 18.2R3-S4, 18.3R2-S4, 18.3R3-S2, 18.4R1-S7, 18.4R3-S2, 19.1R1-S5, 19.1R3-S1, 19.2R2, 19.3R2-S3, 19.3R3, 19.4R1-S2, 19.4R2, 20.1R1-S1, 20.1R2

Timeline

  1. Publicly disclosed

    May 4, 2020

  2. Added to Industry KEV feed

    May 4, 2020

  3. Added to CISA KEV

    Mar 25, 2022

  4. Added to CIRCL KEV

    Mar 25, 2022

  5. Added to ENISA EUVD

    Mar 25, 2022

  6. Last updated

    Oct 24, 2025

Weakness Type

  • CWE-22 Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')
  • CWE-73 External Control of File Name or Path

References

FAQ

Common Questions.

Is CVE-2020-1631 Running On Your Attack Surface?

Brandefense maps vulnerabilities like this one to your internet-facing assets and tells you exactly where to patch.

Request A Demo