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CVE-2023-36846· NVD / CVE Program· CNA juniper

Junos OS: SRX Series: A vulnerability in J-Web allows an unauthenticated attacker to upload arbitrary files

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 user.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. This issue affects Juniper Networks Junos OS on SRX Series: * All versions prior to 20.4R3-S8; * 21.1 versions 21.1R1 and later; * 21.2 versions prior to 21.2R3-S6; * 21.3 versions prior to 21.3R3-S5; * 21.4 versions prior to 21.4R3-S5; * 22.1 versions prior to 22.1R3-S3; * 22.2 versions prior to 22.2R3-S2; * 22.3 versions prior to 22.3R2-S2, 22.3R3; * 22.4 versions prior to 22.4R2-S1, 22.4R3.

MediumCVSS 5.3 · v3.1KEVWeaponized Fix available
Published
Aug 17, 2023
Updated
Jun 17, 2026
EPSS
93.5% · 100th percentile
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Report tools

JSON

Action score

79

This week

Don’t wait for the next maintenance window.

CVSS
21 / 40 · 5.3 / 10
CISA KEV
30 / 30 · Listed
EPSS
28 / 30 · 93.5%

CISA SSVC decision

Exploitation
active
Automatable
yes
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
5.3
CNA · juniper
5.3
agree

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Actively exploited in the wild

CISA added this to its Known Exploited Vulnerabilities catalog on Nov 13, 2023. That signals real attacks, not theory.

Remediation deadline for government agencies: Nov 17, 2023.

Affected systems

VendorProduct
juniperjunos
junipersrx100
junipersrx110
junipersrx1400
junipersrx1500
junipersrx210
junipersrx220
junipersrx240
junipersrx240h2
junipersrx240m
junipersrx300
junipersrx320

and 17 more

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • juniper junosbefore 20.4
  • juniper junos20.4
  • juniper junos21.1
  • juniper junos21.2
  • juniper junos21.3
  • juniper junos21.4
  • juniper junos22.1
  • juniper junos22.2
  • juniper junos22.3
  • juniper junos22.4

Versions reported by the vendor

Affected version ranges reported by the assigning authority (juniper). Independent of NVD's CPE analysis and usually ahead of it.

  • Juniper Networks Junos OS

    • before 20.4R3-S8affected · semver
    • 21.1 and later · before 21.1*affected · semver
    • 21.2 and later · before 21.2R3-S6affected · semver
    • 21.3 and later · before 21.3R3-S5affected · semver
    • 21.4 and later · before 21.4R3-S5affected · semver
    • 22.1 and later · before 22.1R3-S3affected · semver
    • 22.2 and later · before 22.2R3-S2affected · semver
    • 22.3 and later · before 22.3R2-S2, 22.3R3affected · semver
    • 22.4 and later · before 22.4R2-S1, 22.4R3affected · semver

Same product

juniper: all records

Other highest-scoring records for the same primary product.

  • CVE-2023-36845Junos OS: EX and SRX Series: A PHP vulnerability in J-Web allows an unauthenticated to control an important environment variableKEV
    98Now
  • CVE-2023-36844Junos OS: EX Series: A PHP vulnerability in J-Web allows an unauthenticated attacker to control important environment variablesKEV
    78This week
  • CVE-2023-36847Junos OS: EX Series: A vulnerability in J-Web allows an unauthenticated attacker to upload arbitrary filesKEV
    76This week
  • CVE-2020-1631Out of Cycle Security Advisory: Junos OS: Security vulnerability in J-Web and web based (HTTP/HTTPS) servicesKEV
    70This week
  • CVE-2025-21590Junos OS: An local attacker with shell access can execute arbitrary codeKEV
    57Plan
  • CVE-2023-36851Junos OS: SRX Series: A vulnerability in J-Web allows an unauthenticated attacker to upload and download arbitrary filesKEV
    51Plan

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Juniper Networks Junos OS20.4R3-S8Vendor (CNA)
Juniper Networks Junos OS21.1*Vendor (CNA)
Juniper Networks Junos OS21.2R3-S6Vendor (CNA)
Juniper Networks Junos OS21.3R3-S5Vendor (CNA)
Juniper Networks Junos OS21.4R3-S5Vendor (CNA)
Juniper Networks Junos OS22.1R3-S3Vendor (CNA)
Juniper Networks Junos OS22.2R3-S2Vendor (CNA)
Juniper Networks Junos OS22.3R2-S2, 22.3R3Vendor (CNA)
Juniper Networks Junos OS22.4R2-S1, 22.4R3Vendor (CNA)

Exploit status

Weaponized

A ready exploit tool or active in-the-wild use is known for this vulnerability. This should be your top priority.

Evidence

  • Nuclei detection template ×1
  • Proof-of-concept repository on GitHub ×1

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Nuclei detection templateNuclei template CVE-2023-36844 —
Proof-of-concept repository on GitHubstars:52023-08-29

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Published
  2. First PoC+11 d
  3. CISA KEV+87 d
  4. TodaySep 30, 2026+1140 d
EPSS, last 120 days-1% in 7 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
low · data or configuration can be modified
Availability
none
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
Low
Availability impact
None

Weakness class (CWE)

CWE-306 · Missing Authentication for Critical Function

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

nvd-primary

Root cause

A function added for development or support ships to production without authentication. It often relies on the assumption that it is “only reachable from the internal network.”

The bug in code

The whole CWE-306 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

ts
// Added for the support teamapp.post("/maintenance/reset", resetDevice);

Fixed

ts
if (config.maintenanceEnabled) {  app.post(    "/maintenance/reset",    requireSession, requireRole("admin"), resetDevice  );}

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Noroxi analysis

No Noroxi analysis for this record yet

We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.

We use this product, ask for help

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records