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NVD / CVE Program· CNA juniper

CVE-2023-44203: Junos OS: QFX5000 Series, EX2300, EX3400, EX4100, EX4400 and EX4600: Packet flooding will occur when IGMP traffic is sent to an isolated VLAN

MediumCVSS 6.5 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 26/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.30% (FIRST EPSS).
  • Someone on the same network segment can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Juniper Networks Junos OS 20.4R3-S5, 21.1R3-S4, 21.2R3-S3.

Low priority for now. Upgrade to Juniper Networks Junos OS 20.4R3-S5, 21.1R3-S4, 21.2R3-S3 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 · FIRST EPSS

An Improper Check or Handling of Exceptional Conditions vulnerability in the Packet Forwarding Engine (pfe) of Juniper Networks Junos OS on QFX5000 Series, EX2300, EX3400, EX4100, EX4400 and EX4600 allows a adjacent attacker to send specific traffic, which leads to packet flooding, resulting in a Denial of Service (DoS). When a specific IGMP packet is received in an isolated VLAN, it is duplicated to all other ports under the primary VLAN, which causes a flood. This issue affects QFX5000 series, EX2300, EX3400, EX4100, EX4400 and EX4600 platforms only. This issue affects Juniper Junos OS on on QFX5000 Series, EX2300, EX3400, EX4100, EX4400 and EX4600: * All versions prior to 20.4R3-S5; * 21.1 versions prior to 21.1R3-S4; * 21.2 versions prior to 21.2R3-S3; * 21.3 versions prior to 21.3R3-S5; * 21.4 versions prior to 21.4R3-S2; * 22.1 versions prior to 22.1R3; * 22.2 versions prior to 22.2R3; * 22.3 versions prior to 22.3R2.

Published
Oct 12, 2023
Updated
Jun 17, 2026
EPSS
0.3% · 23th percentile

Report tools

JSON

Action score

26

Monitor

Low priority for now.

CVSS
26 / 40 · 6.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.3%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
6.5
CNA · juniper
6.5
agree

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

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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

Follow CVE-2023-44203

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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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.

VendorProduct
juniperjunos
juniperex2300
juniperex2300-24mp
juniperex2300-24p
juniperex2300-24t
juniperex2300-48mp
juniperex2300-48p
juniperex2300-48t
juniperex2300-c
juniperex2300m
juniperex3400
juniperex4100

and 14 more

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-S5affected · semver
    • 21.1 and later · before 21.1R3-S4affected · semver
    • 21.2 and later · before 21.2R3-S3affected · semver
    • 21.3 and later · before 21.3R3-S5affected · semver
    • 21.4 and later · before 21.4R3-S2affected · semver
    • 22.1 and later · before 22.1R3affected · semver
    • 22.2 and later · before 22.2R3affected · semver
    • 22.3 and later · before 22.3R2affected · semver
Affected versions · NVD (9)

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

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-2023-44199Oct 12, 2023 · Junos OS: MX Series: In a PTP scenario a prolonged routing protocol churn can trigger an FPC reboot
    30Monitor
  • ← EarlierCVE-2023-44201Oct 12, 2023 · Junos OS and Junos OS Evolved: A local attacker can retrieve sensitive information and elevate privileges on the device to an authorized user.
    22Monitor
  • Later →CVE-2023-44204Oct 12, 2023 · Junos OS and Junos OS Evolved: The rpd will crash upon receiving a malformed BGP UPDATE message
    26Monitor

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-S5Vendor (CNA)
Juniper Networks Junos OS21.1R3-S4Vendor (CNA)
Juniper Networks Junos OS21.2R3-S3Vendor (CNA)
Juniper Networks Junos OS21.3R3-S5Vendor (CNA)
Juniper Networks Junos OS21.4R3-S2Vendor (CNA)
Juniper Networks Junos OS22.1R3Vendor (CNA)
Juniper Networks Junos OS22.2R3Vendor (CNA)
Juniper Networks Junos OS22.3R2Vendor (CNA)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

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.

No dated events beyond publication.

Not on record for this CVE: EPSS history · patch commit or PR link · researcher credit · variant or chain candidate · public bounty program.

Technical details

Attack conditions

  • Someone on the same network segment 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
none
Availability
high · the service can be disrupted
Attack vector
Adjacent
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-703 · Improper Check or Handling of Exceptional Conditions

CVSS vector

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

nvd-primary

Attack context

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

MITRE has no CAPEC/ATT&CK mapping for this CWE.

References

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

All records