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Full vulnerability report · 2018
CVE-2018-0056High confidence

MX Series: L2ALD daemon may crash if a duplicate MAC is learned by two different interfaces

Juniper Networks · Junos OS

6.5MediumCVSS 3.0
Recommended action
Scheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Patch available
R
Operational reassessment

Published severity in operational context

Open reassessment dashboard →
Published severityMediumOperational priority:Medium, unchanged from published severity.unchanged

Evidence used

  • No CISA KEV confirmation is currently recorded.
  • EPSS is 0.61% for the current model date.

Compensating controls

  • Validate the affected product branch and deploy the verified fixed release.
  • Restrict local access and enforce least privilege on affected hosts.
  • Monitor vendor guidance and exploitation sources for a material change.

Verification

  1. Confirm that the asset runs Juniper Networks 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: As exposure requiresRemediation target: Within 365 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-2018-0880

No EUVD known-exploited evidence

ENISA has published the identifier mapping but no EUVD description has been stored yet.

EUVD state
Present in the current official mapping
Known exploitation
Not present in the current ENISA EUVD known-exploited dataset. This is not proof of no exploitation.
ENISA score
Not supplied in the stored EUVD record
Advisory evidence
No linked advisory details stored yet
Recommended actionScheduled

Medium technical severity with no CISA KEV confirmation; remediate through the normal risk-based patch cycle unless local exposure raises the priority.

Patch available
01

What, why and how

If a duplicate MAC address is learned by two different interfaces on an MX Series device, the MAC address learning function correctly flaps between the interfaces. However, the Layer 2 Address Learning Daemon (L2ALD) daemon might crash when attempting to delete the duplicate MAC address when the particular entry is not found in the internal MAC address table. This issue only occurs on MX Series devices with l2-backhaul VPN configured. No other products or platforms are affected by this issue. Affected releases are Juniper Networks Junos OS: 15.1 versions prior to 15.1R7-S1 on MX Series; 16.1 versions prior to 16.1R4-S12, 16.1R6-S6 on MX Series; 16.2 versions prior to 16.2R2-S7 on MX Series; 17.1 versions prior to 17.1R2-S9 on MX Series; 17.2 versions prior to 17.2R1-S7, 17.2R2-S6 on MX Series; 17.3 versions prior to 17.3R2-S4, 17.3R3-S1 on MX Series; 17.4 versions prior to 17.4R1-S5 on MX Series; 18.1 versions prior to 18.1R2 on MX Series.

What

If a duplicate MAC address is learned by two different interfaces on an MX Series device, the MAC address learning function correctly flaps between the interfaces. However, the Layer 2 Address Learning Daemon (L2ALD) daemon might crash when attempting to delete the duplicate MAC address when the particular entry is not found in the internal MAC address table. This issue only occurs on MX Series devices with l2-backhaul VPN configured. No other products or platforms are affected by this issue. Affected releases are Juniper Networks Junos OS: 15.1 versions prior to 15.1R7-S1 on MX Series; 16.1 versions prior to 16.1R4-S12, 16.1R6-S6 on MX Series; 16.2 versions prior to 16.2R2-S7 on MX Series; 17.1 versions prior to 17.1R2-S9 on MX Series; 17.2 versions prior to 17.2R1-S7, 17.2R2-S6 on MX Series; 17.3 versions prior to 17.3R2-S4, 17.3R3-S1 on MX Series; 17.4 versions prior to 17.4R1-S5 on MX Series; 18.1 versions prior to 18.1R2 on MX Series.

Why

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.

How

An attacker operating through an adjacent network may attempt exploitation without authentication or user interaction. If successful, the issue may disrupt the affected service.

What

If a duplicate MAC address is learned by two different interfaces on an MX Series device, the MAC address learning function correctly flaps between the interfaces. However, the Layer 2 Address Learning Daemon (L2ALD) daemon might crash when attempting to delete the duplicate MAC address when the particular entry is not found in the internal MAC address table. This issue only occurs on MX Series devices with l2-backhaul VPN configured. No other products or platforms are affected by this issue. Affected releases are Juniper Networks Junos OS: 15.1 versions prior to 15.1R7-S1 on MX Series; 16.1 versions prior to 16.1R4-S12, 16.1R6-S6 on MX Series; 16.2 versions prior to 16.2R2-S7 on MX Series; 17.1 versions prior to 17.1R2-S9 on MX Series; 17.2 versions prior to 17.2R1-S7, 17.2R2-S6 on MX Series; 17.3 versions prior to 17.3R2-S4, 17.3R3-S1 on MX Series; 17.4 versions prior to 17.4R1-S5 on MX Series; 18.1 versions prior to 18.1R2 on MX Series.

Why

The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.

How

An attacker operating through an adjacent network may attempt exploitation without authentication or user interaction. If successful, the issue may disrupt the affected service.

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.
No confirmed evidence

No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.

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
an adjacent network → Improper Input Validation → disrupt the affected service
Attack surface
Adjacent
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-20 ↗

CWE-20: Improper Input Validation. The product receives input or data, but it does not validate or incorrectly validates that the input has the properties that are required to process the data safely and correctly.

CVSS vector
?CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity.
CVSS:3.0/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Common Vulnerability Scoring System 3.0: the compact vector below is decoded into plain language.

AVAdjacentAttack vector: The attacker must be on an adjacent or logically close 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.INoneIntegrity impact: No direct loss is represented by this metric.AHighAvailability impact: A successful attack can cause a major loss.
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.
UnauthenticatedDenial of serviceCWE-20
A

Official authority intelligence

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

CERT-FR · French · CERTFR-2018-AVI-487Multiples 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 une exécution de code arbitraire à distance, une exécution de code arbitraire et un déni de service à distance.

Official advisory ↗
JVN iPedia · Japanese · JVNDB-2018-013647Juniper Networks Junos OS における入力確認に関する脆弱性

Juniper Networks Junos OS には、入力確認に関する脆弱性が存在します。

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: 15.1 < 15.1R7-S1, 16.1 < 16.1R4-S12, 16.1R6-S6, 16.2 < 16.2R2-S7, 17.1 < 17.1R2-S9, 17.2 < 17.2R1-S7, 17.2R2-S6, 17.3 < 17.3R2-S4, 17.3R3-S1, 17.4 < 17.4R1-S5, 18.1 < 18.1R2
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. Limit untrusted access and use least privilege until authoritative guidance is available.
04

Evidence and provenance

Published 10 Oct 2018 · Last source change 17 Sept 2024, 02:51 UTC · CWE-20 · Improper Input Validation

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 2026-09-01
European sourceENISA EUVD · EUVD-2018-0880
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceNIST NVD
NVD statusNVD modified after enrichment

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

Material change intelligence

What changed after publication

View recent updates ↗
  1. ENISA EUVD mappingEUVD-2018-0880 was added to the official ENISA EUVD mapping for this CVE.
    Before
    not recorded
    After
    {"euvdId":"EUVD-2018-0880"}
    ENISA EUVD ↗
  2. Vendor guidanceAuthoritative vendor guidance changed: added vendor advisory: kb.juniper.net/JSA10890.
    Before
    no authoritative guidance recorded
    After
    vendor advisory: kb.juniper.net/JSA10890
    kb.juniper.net ↗
  3. Catalogue recordCVE added to the BlackTree catalogue.
    CNA ↗
Material fields only · duplicate refreshes suppressed · history retained for the configured operational retention period
CVE published
ENISA EUVD · EUVD-2018-0880↗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-2018-0056 · cve.blacktree.nl