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Vulnerabilities

Vulnerability · CVE-2023-36851

Juniper Junos OS SRX Series Missing Authentication for Critical Function Vulnerability

Published Aug 29, 2023 · catalog updated Jun 16, 2026 · Juniper Junos OS

Patch now

CVE-2023-36851 is in the CISA known-exploited catalog, due Nov 17, 2023. Confirm Juniper Junos OS against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Severity
Medium5.3
Known exploitation
CISA KEV and VulnCheck KEV
EPSS
1.12%
Remediation
Remediation guidance
Affected products
cpe juniper/junos · vendor Juniper Junos OS

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.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe juniper/junos21.2
  • vendor Juniper Junos OSversion unspecified

How to fix CVE-2023-36851

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

CVE-2023-36851 is in the CISA known-exploited catalog, due Nov 17, 2023. Confirm Juniper Junos OS against the vendor advisory and apply that fix. The CVSS score does not change the priority.

Which versions are affected?

Compare what you have installed with 21.2. Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

What should an analyst verify?

CWE-306: Missing Authentication for Critical Function. EPSS 1.12%. The CISA KEV listing is the exploitation evidence. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

No public source repository is identified for this product.

Timeline

Detection, updates, and resolution for this record.

  1. Sep 27, 2023 · Catalog

    Detected

    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 co

  2. Nov 13, 2023 · CISA KEV

    Known exploited

    Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

  3. Nov 17, 2023 · CISA KEV

    Remediation due

    Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

  4. Jun 16, 2026 · Catalog

    Updated

    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 co

Sources

  • CISA KEVConfirmed exploitationCVE-2023-36851

    Juniper Junos OS on SRX Series contains a missing authentication for critical function vulnerability that 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 arbitrary files via J-Web, leading to a loss of integrity for a certain pa

    cisa.gov
  • CVE.orgVulnerability recordCVE-2023-36851

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2023-36851

    30-day exploitation probability 1.1%

    first.org
  • NIST NVDVulnerability recordCVE-2023-36851

    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 requ

    nvd.nist.gov
  • VulnCheck KEVConfirmed exploitationCVE-2023-36851

    Juniper Junos OS on SRX Series contains a missing authentication for critical function vulnerability that 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

    vulncheck.com

References

Freshness

Last verified in this catalog Oct 17, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.