CVE-2021-0210Network attack vector

Unauthenticated privilege escalation via exposed active session

Published Jan 15, 2021 · Updated Sep 16, 2024

Information exposure in J-Web in Juniper Networks Junos OS allows remote attackers to assume an authenticated user’s privileges. The published record identifies information exposure from an active authenticated session as the enabling condition but does not disclose the affected request, data element, or validation failure. J-Web must be enabled under system services web-management, and an authenticated user must have an active session; the resulting access enables arbitrary command and code execution without interrupting service.

CVSS severity6.8
Medium
EPSS probability1.10%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Information exposure in J-Web in Juniper Networks Junos OS allows remote attackers to assume an authenticated user’s privileges. The published record identifies information exposure from an active authenticated session as the enabling condition but does not disclose the affected request, data element, or validation failure. J-Web must be enabled under system services web-management, and an authenticated user must have an active session; the resulting access enables arbitrary command and code execution without interrupting service.

The record

CVE
CVE-2021-0210
Published
Jan 15, 2021
Updated
Sep 16, 2024
Vendor
Juniper Networks
Product
Junos OS
Classifications
CWE-200
Attack vector
network
Privileges
unauthenticated

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

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=12.3 <12.3R12-S17
  2. Affected versionversion=17.3 <17.3R3-S10
  3. Affected versionversion=17.4 <17.4R2-S12, 17.4R3-S3
  4. Affected versionversion=18.1 <18.1R3-S11
  5. Affected versionversion=18.2 <18.2R3-S6
  6. Affected versionversion=18.3 <18.3R2-S4, 18.3R3-S4
  7. Affected versionversion=18.4 <18.4R2-S5, 18.4R3-S5
  8. Affected versionversion=19.1 <19.1R1-S6, 19.1R2-S2, 19.1R3-S3
  9. Affected versionversion=19.2 <19.2R1-S5, 19.2R3, 19.2R3-S1
  10. Affected versionversion=19.3 <19.3R2-S4, 19.3R3
  11. Affected versionversion=19.4 <19.4R1-S3, 19.4R2-S2, 19.4R3
  12. Affected versionversion=20.1 <20.1R1-S4, 20.1R2
  13. Affected versionversion=20.2 <20.2R1-S1, 20.2R2

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Juniper Networks · Junos OSversion=12.3 <12.3R12-S17; version=17.3 <17.3R3-S10; version=17.4 <17.4R2-S12, 17.4R3-S3; version=18.1 <18.1R3-S11; version=18.2 <18.2R3-S6; version=18.3 <18.3R2-S4, 18.3R3-S4; version=18.4 <18.4R2-S5, 18.4R3-S5; version=19.1 <19.1R1-S6, 19.1R2-S2, 19.1R3-S3; version=19.2 <19.2R1-S5, 19.2R3, 19.2R3-S1; version=19.3 <19.3R2-S4, 19.3R3; version=19.4 <19.4R1-S3, 19.4R2-S2, 19.4R3; version=20.1 <20.1R1-S4, 20.1R2; version=20.2 <20.2R1-S1, 20.2R2

Published CVSS scores

6.8Juniper NetworksCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:N
5.0NVDAV:N/AC:L/Au:N/C:P/I:N/A:N

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)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-200Information Exposure

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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