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Full vulnerability report · 2023
CVE-2023-36851High confidence

Juniper Junos OS SRX Series Missing Authentication for Critical Function Vulnerability

Juniper · Junos OS

5.3MediumCVSS 3.1
Recommended action
Patch now

CISA confirms exploitation in the wild and lists 2023-11-17 as the remediation due date.

Patch available
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityMediumOperational priority:Critical, raised 2 bands.upgradedsince 13 Nov 2023

Evidence used

  • CISA confirms exploitation in the wild.
  • The selected CVSS metric records a network-reachable, unauthenticated path with no user interaction.
  • EPSS is 1.12% for the current model date.

Compensating controls

  • Validate the affected product branch and deploy the verified fixed release.
  • Restrict the affected network interface to trusted sources where business-safe.
  • Increase monitoring for the attack path and post-exploitation behaviour described in the report.

Verification

  1. Confirm that the asset runs Juniper Junos OS and falls inside the recorded affected range.
  2. Verify the installed build against the product-specific fixed version after deployment.
  3. Validate exposure, authentication requirements and compensating controls in the actual environment.
  4. Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
Mitigation target: Within 3 daysRemediation target: Within 90 days

This automated reassessment organises public evidence. It does not know asset exposure, business impact or control effectiveness and does not replace CVSS or a human risk decision.

Optional official sources

National CERT insights
?CERT means Computer Emergency Response Team; CSIRT is the closely related term Computer Security Incident Response Team.

Choose official national sources for this report. Each advisory shows its original language. Your selection is remembered on this device and included in shared links.

Official European source

ENISA European Vulnerability Database

Official EUVD identifiers, advisory evidence and known-exploited context. Missing fields are not treated as evidence of low risk.

1 current
ENISA EUVD identifier

EUVD-2023-40771

CISA KEV mirrored by ENISA

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.

EUVD state
Present in the current official mapping
Known exploitation
Recorded by ENISA since 13 Nov 2023. Evidence sources: cisa_kev.
ENISA score
5.3 · CVSS 3.1
Advisory evidence
1 linked advisory record
Recommended actionPatch now

CISA confirms exploitation in the wild and lists 2023-11-17 as the remediation due date.

Patch available
01

What, why and how

Juniper Junos OS on SRX Series contains a missing authentication for critical function vulnerability that 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 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.

What

Juniper Junos OS on SRX Series contains a missing authentication for critical function vulnerability that 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 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.

Why

A security-sensitive function is reachable without the authentication check that should protect it.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

What

Juniper Junos OS on SRX Series contains a missing authentication for critical function vulnerability that 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 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.

Why

A security-sensitive function is reachable without the authentication check that should protect it.

How

An attacker operating through a network path may attempt exploitation without authentication or user interaction. If successful, the issue may cause the confidentiality, integrity or availability impact described by the vendor.

02

Exploit reality and attack path

CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.

Observed exploitation
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
Confirmed in the wild

CISA added this CVE to its Known Exploited Vulnerabilities catalogue on 2023-11-13.

Public PoC / exploit material
?Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.
None recorded

No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.

Likely attack path
a network path → Missing Authentication for Critical Function → cause the confidentiality, integrity or availability impact described by the vendor
Attack surface
Network
Privileges required
None: unauthenticated exploitation is possible
User interaction
None
Attack complexity
Low: no specialised conditions are recorded
Security boundary
Unchanged: impact remains within the vulnerable component's security authority
Weakness
?CWE means Common Weakness Enumeration: a standard category for the underlying weakness.
CWE-306 ↗

CWE-306: Missing Authentication for Critical Function. The product does not perform any authentication for functionality that requires a provable user identity or consumes a significant amount of resources.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Common Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.

AVNetworkAttack vector: The vulnerable component can be reached over a network.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRNonePrivileges required: The attacker does not need an account or existing privileges.UINoneUser interaction: No action by another user is required.SUnchangedScope: The security impact remains within the vulnerable component's authority.CNoneConfidentiality impact: No direct loss is represented by this metric.ILowIntegrity impact: A successful attack can cause a limited loss.ANoneAvailability impact: No direct loss is represented by this metric.
Post-exploitation / living off the land
No specific living-off-the-land technique is confirmed in the structured sources. Monitor normal administration tools for activity inconsistent with the affected service's baseline.
NetworkUnauthenticatedCWE-306CISA KEV
A

Official authority intelligence

Only matched European and national findings are included. Language selectors and unavailable sources are omitted.

ENISA EUVD · EUVD-2023-40771Known-exploited evidence recorded

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.

Official EUVD record ↗
BSI · German · WID-SEC-2023-2092Juniper JUNOS: Mehrere Schwachstellen ermöglichen Codeausführung

Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in Juniper JUNOS auf Geräten der EX- und SRX Serie ausnutzen, um beliebigen Programmcode auszuführen.

Official advisory ↗
Cyber Security Agency of Singapore · English · CSA-SB-20231004Security Bulletin 04 Oct 2023

The Cyber Security Agency of Singapore included this CVE in its official Security Bulletin 04 Oct 2023, published on 4 October 2023. Open the linked bulletin for the product, severity and reference information published in that issue.

Official advisory ↗
CERT-FR · French · CERTFR-2024-AVI-0072Multiples vulnérabilités dans les produits Juniper

De multiples vulnérabilités ont été découvertes dans les produits Juniper. Certaines d'entre elles permettent à un attaquant de provoquer un contournement de la politique de sécurité, une atteinte à l'intégrité des données et une atteinte à la confidentialité des données.

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2023-013125ジュニパーネットワークスの Junos OS における重要な機能に対する認証の欠如に関する脆弱性

ジュニパーネットワークスの Junos OS には、重要な機能に対する認証の欠如に関する脆弱性が存在します。

Official advisory ↗
KISA KrCERT/CC · Korean · KNVD-6038美 CISA 발표 주요 Exploit 정보공유(Update. 2023-11-13)

Juniper Junos OS on SRX Series contains a missing authentication for critical function vulnerability that 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 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.

Official advisory ↗
03

Patch and workaround

Operational remediation based on structured source evidence.

Status
?Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change.
Patch available
Affected
Junos OS: 22.3 < 22.3R3-S2, 23.2 < 23.2R1-S2, 23.2R2, 22.1 < 22.1R3-S5, 21.2 < 21.2R3-S8, 21.4 < 21.4R3-S6, 22.2 < 22.2R3-S3, 22.4 < 22.4R2-S2, 22.4R3
Fixed
Action
Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
Workaround
No verified workaround is recorded. If business-safe, reduce exposure to the affected interface and allow only trusted sources until authoritative guidance is available.
04

Evidence and provenance

Published 26 Sept 2023 · Last source change 21 Oct 2025, 23:05 UTC · CWE-306 · Missing Authentication for Critical Function

CVE recordCVE.org · 5.1
CVSS sourceCNA
EPSS source
?The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.
FIRST · tracked since 2026-08-14
European sourceENISA EUVD · EUVD-2023-40771
Product sourceCISA KEV
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD enriched

Core structured fields are present and their contributing authorities are shown above.

Material change intelligence

What changed after publication

View recent updates ↗
  1. Vendor guidanceAuthoritative vendor guidance changed: added remediation: supportportal.juniper.net/JSA72300.
    Before
    vendor advisory: supportportal.juniper.net/JSA72300
    After
    remediation: supportportal.juniper.net/JSA72300 · vendor advisory: supportportal.juniper.net/JSA72300
    supportportal.juniper.net ↗
  2. Affected versionsThe structured affected or fixed version information changed.
    Before
    21.2 < 21.2R3-S8; 21.4 < 21.4R3-S6; 22.1 < 22.1R3-S5; 22.2 < 22.2R3-S3; 22.3 < 22.3R3-S2; 22.4 < 22.4R2-S2, 22.4R3; 23.2 < 23.2R1-S2, 23.2R2 · Fixed: No fixed version is explicitly recorded in the structured CVE data.
    After
    Junos OS: 21.2 < 21.2R3-S8, 21.4 < 21.4R3-S6, 22.1 < 22.1R3-S5, 22.2 < 22.2R3-S3, 22.3 < 22.3R3-S2, 22.4 < 22.4R2-S2, 22.4R3, 23.2 < 23.2R1-S2, 23.2R2 · Fixed: The following software releases have been updated to resolve this specific issue: 21.2R3-S8*, 21.4R3-S6*, 22.1R3-S5*, 22.2R3-S3*, 22.3R3-S2*, 22.4R2-S2, 22.4R3*, 23.2R1-S2, 23.2R2*, 23.4R1, and all subsequent releases.; *Pending Publication
    CNA ↗
  3. Remediation statusRemediation status changed from Awaiting fix to Patch available.
    Before
    Awaiting fix
    After
    Patch available
    supportportal.juniper.net ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
Added to CISA KEV
Fixed release or patch reference recorded
ENISA EUVD · EUVD-2023-40771↗CISA KEV record↗CVE authority or vendor reference↗Official CVE record (CNA and ADP data)↗NVD record↗
Technical terms and abbreviations used in this report
CVE
Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
CVSS
Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
EPSS
Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
CWE
Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
CNA
CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
CISA ADP
Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
NVD
National Vulnerability Database: NIST's enrichment service for CVE records.
CERT / CSIRT
A computer security incident response team that publishes warnings or coordinates incident response.
PoC
Proof of concept: public material that demonstrates or helps reproduce exploitation.
CSAF
Common Security Advisory Framework: a machine-readable format for security advisories.
LoTL
Living off the land: abuse of legitimate tools or system functions during an attack.
Free version - for non-commercial use only.CVE-2023-36851 · cve.blacktree.nl