CVE-2021-0218Known exploitationPublic exploit

Root command execution via unsanitized license URL

Published Jan 15, 2021 · Updated Sep 16, 2024

Command injection in Junos OS license-check daemon allows local authenticated users to execute root commands via the license update CLI. The mgd_update_license function writes a user-controlled url into /tmp/.autoupdate, and lc_fetch_license_keys passes that content into a system() command without sanitization. Exploitation requires maintenance-level access to request system license update, or shell access combined with automatic license updates; successful execution runs with the daemon's root privilege.

CVSS severity7.8
High
EPSS probability0.85%
Next 30 days · Sep 16, 2026
Known exploitationReported
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Command injection in Junos OS license-check daemon allows local authenticated users to execute root commands via the license update CLI. The mgd_update_license function writes a user-controlled url into /tmp/.autoupdate, and lc_fetch_license_keys passes that content into a system() command without sanitization. Exploitation requires maintenance-level access to request system license update, or shell access combined with automatic license updates; successful execution runs with the daemon's root privilege.

The record

CVE
CVE-2021-0218
Published
Jan 15, 2021
Updated
Sep 16, 2024
Vendor
Juniper Networks
Product
Junos OS
Classifications
CWE-78, T1059
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 15, 2021CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=17.3 <17.3R3-S9
  2. Affected versionversion=17.4 <17.4R2-S12, 17.4R3-S3
  3. Affected versionversion=18.1 <18.1R3-S11
  4. Affected versionversion=18.2 <18.2R3-S6
  5. Affected versionversion=18.3 <18.3R3-S4
  6. Affected versionversion=18.4 <18.4R3-S6
  7. Affected versionversion=19.1 <19.1R1-S6, 19.1R2-S2, 19.1R3-S3
  8. Affected versionversion=19.2 <19.2R3-S1
  9. Affected versionversion=19.3 <19.3R2-S5, 19.3R3
  10. Affected versionversion=19.4 <19.4R2-S2, 19.4R3
  11. Affected versionversion=20.1 <20.1R1-S4, 20.1R2
  12. Affected versionversion=20.2 <20.2R1-S2, 20.2R2

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

Juniper Networks · Junos OSversion=17.3 <17.3R3-S9; version=17.4 <17.4R2-S12, 17.4R3-S3; version=18.1 <18.1R3-S11; version=18.2 <18.2R3-S6; version=18.3 <18.3R3-S4; version=18.4 <18.4R3-S6; version=19.1 <19.1R1-S6, 19.1R2-S2, 19.1R3-S3; version=19.2 <19.2R3-S1; version=19.3 <19.3R2-S5, 19.3R3; version=19.4 <19.4R2-S2, 19.4R3; version=20.1 <20.1R1-S4, 20.1R2; version=20.2 <20.2R1-S2, 20.2R2

Published CVSS scores

7.8Juniper NetworksCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationReported
Public exploitPublished

Weakness, pattern, technique

CWE-78OS Command Injection
T1059Command and Scripting Interpreter

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Reported exploitation

Technologies

Your stack

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Your stack

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