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CVE-2023-36851

Junos OS: SRX Series: A vulnerability in J-Web allows an unauthenticated attacker to upload and download arbitrary files

  • Medium 5.3
  • Exploited: added to CISA KEV 13 Nov 2023

Description

A Missing Authentication for Critical Function vulnerability in Juniper Networks Junos OS on SRX Series allows an unauthenticated, network-based attacker to cause limited impact to the file system integrity. With a specific request to webauth_operation.php that doesn't require authentication, an attacker is able to upload and download arbitrary files via J-Web, leading to a loss of integrity or confidentiality, which may allow chaining to other vulnerabilities. This issue affects Juniper Networks Junos OS on SRX Series: * 21.2 versions prior to 21.2R3-S8; * 21.4 versions prior to 21.4R3-S6; * 22.1 versions prior to 22.1R3-S5; * 22.2 versions prior to 22.2R3-S3; * 22.3 versions prior to 22.3R3-S2; * 22.4 versions prior to 22,4R2-S2, 22.4R3; * 23.2 versions prior to 23.2R1-S2, 23.2R2.

Key facts

Published
26 Sep 2023
Last changed
21 Oct 2025
Assigned by
juniper
KEV added
13 Nov 2023
KEV fix due
17 Nov 2023
EPSS
1.123% likely to be exploited in the next 30 days, higher than 66.77% of CVEs (scores for 15 Nov 2026)
SSVC (CISA)
Exploitation: active; Automatable: yes; Technical impact: total

Severity scores

Each score is shown as its source gave it. They are not averaged or merged.

  • 5.3CVSS 3.1, Mediumfrom the CNA (juniper)CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

What to do

  • The following software releases have been updated to resolve this specific issue: 21.2R3-S8*, 21.4R3-S6*, 22.1R3-S5*, 22.2R3-S3*, 22.3R3-S2*, 22.4R2-S2, 22.4R3*, 23.2R1-S2, 23.2R2*, 23.4R1, and all subsequent releases. *Pending PublicationCNA solution statement
  • Disable J-Web, or limit access to only trusted hosts.CNA workaround statement
  • Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.CISA KEV required action

Historical context and remediation

This reference retains the original CVE publication date. A recent record update does not mean a new attack occurred.

No separately sourced impact summary is available on this page yet. Consult the description, version data and dated exploitation evidence.

Version statuses below come from the CNA. An “unaffected” version is not necessarily a currently supported release or proof of a patch date. EPSS is a dated risk estimate, not a count of historical attacks.

Read the original CVE record.

Affected products

VendorProductVersions
Juniper NetworksJunos OS
  • Default status: unaffected
  • 21.2 up to but excluding 21.2R3-S8 (affected)
  • 21.4 up to but excluding 21.4R3-S6 (affected)
  • 22.1 up to but excluding 22.1R3-S5 (affected)
  • 22.2 up to but excluding 22.2R3-S3 (affected)
  • 22.3 up to but excluding 22.3R3-S2 (affected)
  • 22.4 up to but excluding 22.4R2-S2, 22.4R3 (affected)
  • 23.2 up to but excluding 23.2R1-S2, 23.2R2 (affected)

Timeline

  1. 5 Sep 2023 Initial CVE publication
  2. 26 Sep 2023 Published
  3. 8 Nov 2023 Juniper SIRT is now aware of successful exploitation
  4. 13 Nov 2023 CVE-2023-36851 added to CISA KEV
  5. 13 Nov 2023 Added to the CISA KEV catalogue

Weakness

References