CVE-2023-36851
Access Control in Juniper Junos 21.2 … 23.2
Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:NCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2023-36851 is a medium-severity Missing Authentication for Critical Function (CWE-306) vulnerability in Juniper Junos. Its CVSS base score is 5.3 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique System Service Discovery (T1007); ranked in the top 34% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2023-36851 is a missing authentication for critical function vulnerability (CWE-306) affecting Juniper Networks Junos OS on SRX Series devices. The flaw resides in the J-Web interface and permits an unauthenticated network attacker to reach the script webauth_operation.php, which lacks any access control. Affected releases include all 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 and 22.4R3, and 23.2 versions prior to 23.2R1-S2 and 23.2R2. The CVSS 3.1 base score is 5.3.
An unauthenticated remote attacker can send a crafted request to webauth_operation.php to upload or download arbitrary files on the device file system. The action results in limited integrity and confidentiality impact and may be chained with other vulnerabilities to expand access.
The vendor advisory JSA72300 lists the fixed releases above and is referenced by CISA in its Known Exploited Vulnerabilities catalog, confirming that exploitation has been observed in the wild. The associated EPSS score has reached a peak of 0.1563.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2023-40771
Vulnerability Data
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…
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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.
- CWE(s)
- KEV Date Added
- 13 November 2023
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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- 6 hardening rules · 3 OS baselines
V6.2.3V6.4.4V10.4.16V12.1.3
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Requires established identification and authentication to unlock, mitigating missing authentication for continued system access.
Requiring identification and rationale for actions allowed without authentication ensures critical functions are not left unprotected by forcing review of authentication requirements.
Authorizing mobile device connections to organizational systems ensures authentication is performed for this critical access function.
Guarantees critical functions are protected by mandatory invocation of the access control mechanism.
Auditing sessions makes it possible to detect access to critical functions without required authentication.
The assessment process confirms authentication is present and effective for critical functions, preventing exploitation from missing authentication.
Certification assesses that critical functions have required authentication controls in place.
Disabling non-essential functions and services eliminates the need to secure them, reducing exposure from missing authentication on unnecessary components.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Managing identities and credentials is a prerequisite for authentication but does not itself enforce it on critical functions.
Directly requires authentication of users/services/hardware, which eliminates missing authentication for critical functions.
Defining and enforcing authorizations assumes prior authentication and therefore only partially mitigates the absence of authentication.
Protecting networks from unauthorized access can be undermined by missing authentication but does not address the root authentication gap.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Mandating authentication requirements for critical functions at the requirements-gathering stage ensures that essential operations are not left unprotected by missing login or verification mechanisms.
Hardening callouts derived
Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (higher-evidence rows only; rows rated `none` are excluded).
Oracle Linux 8 (2 rules)
- V-248585 OL 8 must require reauthentication when using the "sudo" command. blocks CWE-306
- V-248827 OL 8 must not have the rsh-server package installed. blocks CWE-306
RHEL 7 (2 rules)
- V-204442 The Red Hat Enterprise Linux operating system must not have the rsh-server package installed. blocks CWE-306
- V-237635 The Red Hat Enterprise Linux operating system must require re-authentication when using the "sudo" command. blocks CWE-306
RHEL 8 (2 rules)
- V-230492 RHEL 8 must not have the rsh-server package installed. blocks CWE-306
- V-237643 RHEL 8 must require re-authentication when using the "sudo" command. blocks CWE-306