Skip to content
TrackCVE
  • Newest CVEsPage
  • Recently added to KEVPage
  • Rising exploitation (EPSS)Page
  • Weekly digestPage
  • StatisticsPage
  • WatchlistPage
  • API documentationPage
  • MCP serverPage
  • Data sourcesPage
  • ChangelogPage
  • AboutPage
  • How it's builtPage
Back

CVE-2021-31357

Junos OS Evolved: shell-injection vulnerabilities in evo_tcpdump UI wrapper script

High7.8EPSS 0.63%
Published
Updated
Reserved
Assigned by
juniper

Description

A command injection vulnerability in tcpdump command processing on Juniper Networks Junos OS Evolved allows an attacker with authenticated CLI access to be able to bypass configured access protections to execute arbitrary shell commands within the context of the current user. The vulnerability allows an attacker to bypass command authorization restrictions assigned to their specific user account and execute commands that are available to the privilege level for which the user is assigned. For example, a user that is in the super-user login class, but restricted to executing specific CLI commands could exploit the vulnerability to execute any other command available to an unrestricted admin user. This vulnerability does not increase the privilege level of the user, but rather bypasses any CLI command restrictions by allowing full access to the shell. This issue affects Juniper Networks Junos OS Evolved: All versions prior to 20.3R2-S1-EVO; 20.4 versions prior to 20.4R2-S2-EVO; 21.1 versions prior to 21.1R2-EVO; 21.2 versions prior to 21.2R1-S1-EVO, 21.2R2-EVO.

Timeline

  1. ID reserved

    By juniper

  2. · 6 months later

    Published

  3. · 3 years later

    Record updated

Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.

Scores

CVSS scores of CVE-2021-31357, by who scored it
Scored byCVSSScoreVector
juniperCNA (assigner)3.1High7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
NVDNVD · Modified3.1High7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS (exploitation in 30 days)
0.63% · top 50% of all CVEs (7 Nov 2026)
Loading the EPSS history…

The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.8.

Weakness

Affected products

  • Juniper Networks · Junos OS Evolved

    • affected unspecified – < 20.3R2-S1-EVO
    • affected 20.4 – < 20.4R2-S2-EVO
    • affected 21.1 – < 21.1R2-EVO
    • affected 21.2 – < 21.2R1-S1-EVO, 21.2R2-EVO

What to do

Solution: The following software releases have been updated to resolve this specific issue: Junos OS Evolved 20.3R2-S1-EVO, 20.4R2-S2-EVO, 21.1R2-EVO, 21.2R1-S1-EVO, 21.2R2-EVO, 21.3R1-EVO, and all subsequent releases.

Workaround: Use access lists or firewall filters to limit access to the device via CLI only from trusted hosts and from trusted administrators. Limit access to the 'monitor traffic' command to authorized administrators.

Exploitation: Juniper SIRT is not aware of any malicious exploitation of this vulnerability.

References (1)

Sources

The same CVE in the primary databases and aggregators, to check against.

Badge for a README or a ticket

CVE-2021-31357 badge
[![CVE-2021-31357](https://trackcve.app/badge/CVE-2021-31357.svg)](https://trackcve.app/cve/CVE-2021-31357)

Record last updated .