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CVE-2023-36851

KEVJuniper Junos OS SRX Series Missing Authentication for Critical Function Vulnerability

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.

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.

CVSS 3.1 vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
PublishedSep 27, 2023
Last modifiedJun 17, 2026
Added to KEVNov 13, 2023
Remediation dueNov 17, 2023
    57
    Risk assessment · Medium

    Actively exploited. Patch immediately.

    Exploitation
    Confirmed in the wild (CISA KEV)
    Federal remediation deadline
    Overdue by 1076 days
    CVSS
    5.3 MEDIUM
    EPSS (30-day exploit probability)
    1.1% · top 34% of all CVEs
    Weakness
    CWE-306
    Attack vector
    Network, remotely reachable
    Preconditions
    No privileges and no user interaction
    1. 1.Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
    2. 2.Treat as emergency change: patch or isolate internet-facing instances first.
    3. 3.Review exposure: confirm which instances are reachable from the internet and restrict access until patched.
    4. 4.Hunt for compromise: review logs for the disclosure window, not just from the patch date.

    Assessment is derived automatically from the live signals above; verify against your own asset inventory.