Threats / Juniper / CVE-2023-36846
CVE-2023-36846
· EUVD no mirror located
· GCVE no mirror located
Verified 2026-06-22
Juniper Junos OS vulnerability
Juniper Junos OS on SRX Series contains a missing authentication vulnerability in J-Web that allows unauthenticated attackers to upload arbitrary files, compromising file system integrity.
Verdict
Today item — known-exploited.
An unauthenticated network attacker can exploit a missing authentication check in the user.php endpoint to upload malicious files via J-Web, potentially enabling further compromise of the device.
01
Is it exploitable?
— the evidence, ranked above the scoreExploit available
Fully weaponized — public exploit code is cataloged for this vulnerability.We link the existence of the exploit; we do not host or redistribute payloads.
Reported exploitation
18 independent public reports of in-the-wild exploitation are cataloged.Distinct reporting sources (vendor, incident response, government); open them for the underlying claims.
Exploited in the wild
Listed in the CISA Known Exploited Vulnerabilities catalog (added 2023-11-13).
Probability (EPSS)
EPSS 0.94205 — modeled likelihood of exploitation activity.EPSS is a daily-changing model output — open the source for today's value.
Severity / affected
Affected: Juniper, Junos OS. Confirm exact fixed builds in the vendor advisory.
Weakness (CWE)
Mapped to CWE-306 Missing Authentication — weakness family: Authentication.CWE assignment from the public NVD record; the weakness class drives how the flaw is exploited.
02
Who’s exploiting it?
— attribution turns risk into urgencyAttribution not established
No confirmed (advisory-backed) threat-actor attribution is established for this record. Absence of a named actor is not absence of compromise — see Coverage & confidence.
03
Why it matters
— the attack path, told twice: adversary, then board1
Front door — unauthenticated access narrative 1
Attacker
I identify that the user.php endpoint in J-Web lacks authentication controls.
Business
The organization's SRX device perimeter security is exposed to unauthorized file upload attacks without credential requirements.
2
Keys to the kingdom — privilege/identity takeover narrative 2
Attacker
I craft a request to upload arbitrary files to the device file system without providing valid credentials.
Business
Malicious files are written to the device, degrading the integrity of critical system components.
3
Lateral reach — past segmentation narrative 3
Attacker
I chain this file upload capability with other vulnerabilities to achieve deeper system compromise.
Business
The organization faces potential loss of device control, configuration tampering, or lateral movement into the network.
04
What to do
— defensible action- Remediate per the vendor advisory — confirm the fixed build for your version and verify exposure.1
Say it to the boardA vulnerability with this evidence profile is a defensible budget line, not a backlog ticket — fund the change against the proof above.
05
Coverage & confidence
— what we know, and what we don’tEstablished (cited)
Coverage gaps — stated, not hidden
Disclosure & credit2
Catalogued by juniperCNA
Credited with finding itLYS, working with DEVCORE Internship Programfinder