CVE-2023-36851
MEDIUMCVE-2023-36851 is a medium-severity (CVSS 5.3) Missing Authentication vulnerability. It is in CISA's Known Exploited Vulnerabilities catalog (added 2023-11-13) — treat it as actively exploited and patch now. No vendor fix is recorded yet; mitigation options are listed below.
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…
Exploitation Status
Actively exploited in the wild
- Confirmed by CISA's Known Exploited Vulnerabilities catalog on 2023-11-13. Federal agencies were required to remediate by 2023-11-17.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA (KEV catalog and SSVC triage) for CVE-2023-36851.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2023-36851 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 394,803 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
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.
Affected Products
junosjuniperResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
VulnerabilityDetect
Identify every host running the affected component and compare the installed build against the fixed version below — for source-built or distro-packaged software the version string, not a lockfile, is the source of truth (`dpkg -l`, `rpm -q`, or the binary's own `--version`).
Remediation status
No fixed release is recorded for CVE-2023-36851 yet. Track the upstream advisory, and apply the exposure-reduction steps below in the meantime.
Mitigate without a patch
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.
Frequently Asked Questions
Is CVE-2023-36851 in your dependencies?
Find it across , including transitive dependencies.