CVE-2023-36851

What the flaw is

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 part of the file system, which may allow chaining to other vulnerabilities.

Description as published by CISA. We have not independently reproduced it.

What CISA requires

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

This deadline is binding on US federal civilian agencies under BOD 22-01. It is not a legal deadline for anyone else, but it is a useful urgency signal — CISA sets it by how actively the flaw is being used, not by CVSS.

Public exploit code

2 public repositories referencing this CVE have been catalogued on GitHub. Treat this as a strong signal to prioritise patching, not as a verified working exploit — many such repositories are scanners, write-ups or forks rather than functional code.

• Ostorlab/KEV
• Ostorlab/known_exploited_vulnerbilities_detectors

Vendor advisories

• supportportal.juniper.net/s/article/2023-08-Out-of-Cycle-Security-Bulletin-Jun
• nvd.nist.gov/vuln/detail/CVE-2023-36851

Primary sources

• NVD entry — CVSS score, CPE list and references
• CISA KEV catalog — the source for this page
• CVE Record at cve.org