NVD / CVE Program· CNA juniper

CVE-2023-36851: Junos OS: SRX Series: A vulnerability in J-Web allows an unauthenticated attacker to upload and download arbitrary files

MediumCVSS 5.3 · v3.1KEVWeaponized Fix available

Noroxi assessment

Priority: This week (action score 60/100)

CISA has confirmed exploitation in the wild (Nov 13, 2023). Remediation deadline for US federal agencies: Nov 17, 2023.
A ready-made attack tool exists and the flaw can be exploited over the network without an account, so priority is at least “This week”.
Probability of exploitation in the next 30 days: 1.1% (FIRST EPSS); higher than 66.6% of all records.
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.
According to CISA the attack is automatable: targets can be found by mass scanning.
Fixed version: Juniper Networks Junos OS 21.2R3-S8, 21.4R3-S6, 22.1R3-S5.

Don’t wait for the next maintenance window. Upgrade to Juniper Networks Junos OS 21.2R3-S8, 21.4R3-S6, 22.1R3-S5 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · CISA KEV · FIRST EPSS

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.

BDU:2023-07267

Published: Sep 27, 2023
Updated: Jun 17, 2026
EPSS: 1.1% · 66th percentile
CWE: CWE-306

Report tools

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Action score

This week

Don’t wait for the next maintenance window.

CVSS: 21 / 40 · 5.3 / 10
CISA KEV: 30 / 30 · Listed
EPSS: 0 / 30 · 1.1%
Ready-made attack tool: 9 / 60 · floor: at least 60

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 US federal agencies: Nov 17, 2023.

Get told when this record changes

In CISA KEV: exploitation in the wild confirmed
Weaponized exploit exists
A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Is your version affected? Check it

Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
juniper	junos	cpe:2.3:o:juniper:junos
juniper	ex2200	cpe:2.3:h:juniper:ex2200
juniper	ex2200-c	cpe:2.3:h:juniper:ex2200-c
juniper	ex2200-vc	cpe:2.3:h:juniper:ex2200-vc
juniper	ex2300	cpe:2.3:h:juniper:ex2300
juniper	ex2300-24mp	cpe:2.3:h:juniper:ex2300-24mp
juniper	ex2300-24p	cpe:2.3:h:juniper:ex2300-24p
juniper	ex2300-24t	cpe:2.3:h:juniper:ex2300-24t
juniper	ex2300-48mp	cpe:2.3:h:juniper:ex2300-48mp
juniper	ex2300-48p	cpe:2.3:h:juniper:ex2300-48p
juniper	ex2300-48t	cpe:2.3:h:juniper:ex2300-48t
juniper	ex2300-c	cpe:2.3:h:juniper:ex2300-c

and 80 more

Affected versions

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

juniper junos21.2
juniper junos21.4
juniper junos22.1
juniper junos22.2
juniper junos22.3
juniper junos22.4
juniper junos23.2

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
- 21.2 and later · before 21.2R3-S8affected · semver
- 21.4 and later · before 21.4R3-S6affected · semver
- 22.1 and later · before 22.1R3-S5affected · semver
- 22.2 and later · before 22.2R3-S3affected · semver
- 22.3 and later · before 22.3R3-S2affected · semver
- 22.4 and later · before 22.4R2-S2, 22.4R3affected · semver
- 23.2 and later · before 23.2R1-S2, 23.2R2affected · 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-2023-36846Junos OS: SRX Series: A vulnerability in J-Web allows an unauthenticated attacker to upload arbitrary filesKEV
79This week
CVE-2023-36844Junos OS: EX Series: A PHP vulnerability in J-Web allows an unauthenticated attacker to control important environment variablesKEV
78This week

Published before and after this one in the same product

← EarlierCVE-2023-36847Aug 17, 2023 · Junos OS: EX Series: A vulnerability in J-Web allows an unauthenticated attacker to upload arbitrary filesKEV
76This week
← EarlierCVE-2023-4481Aug 31, 2023 · Junos OS and Junos OS Evolved: A crafted BGP UPDATE message allows a remote attacker to de-peer (reset) BGP sessions (CVE-2023-4481)
36Monitor
Later →CVE-2023-44186Oct 11, 2023 · Junos OS and Junos OS Evolved: RPD crash when attempting to send a very long AS PATH to a non-4-byte-AS capable BGP neighbor
30Monitor

Remediation

Which version to upgrade to

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

Product / package	Fixed version	Source
Juniper Networks Junos OS	21.2R3-S8	Vendor (CNA)
Juniper Networks Junos OS	21.4R3-S6	Vendor (CNA)
Juniper Networks Junos OS	22.1R3-S5	Vendor (CNA)
Juniper Networks Junos OS	22.2R3-S3	Vendor (CNA)
Juniper Networks Junos OS	22.3R3-S2	Vendor (CNA)
Juniper Networks Junos OS	22.4R2-S2, 22.4R3	Vendor (CNA)
Juniper Networks Junos OS	23.2R1-S2, 23.2R2	Vendor (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.

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.

PublishedSep 27, 2023
CISA KEVNov 13, 2023+47 d
TodayNov 12, 2026+1142 d

No history yet (it accumulates with the daily EPSS job).

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.

watchtowrfinder

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

1// Added for the support team
2app.post("/maintenance/reset", resetDevice);

Fixed

1if (config.maintenanceEnabled) {
2  app.post(
3    "/maintenance/reset",
4    requireSession, requireRole("admin"), resetDevice
5  );
6}

Attack context

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

Attack patterns (CAPEC)

ATT&CK techniques

—

Change log

Fix✗ → ✓Sep 28, 2026, 10:09 PM UTC

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

References

supportportal.juniper.net/JSA72300

Show all references (1 more)

www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-36851

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

All records