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CVE-2018-18066: snmp_oid_compare in snmplib/snmp_api.c in Net-SNMP before 5.8 has a NULL Pointer Exception bug that can be...

snmp_oid_compare in snmplib/snmp_api.c in Net-SNMP before 5.8 has a NULL Pointer Exception bug that can be used by an unauthenticated attacker to remotely cause the instance to crash via a crafted UDP packet, resulting in Denial of Service.

HighCVSS 7.5Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2018-18066 is a remote denial-of-service flaw in Net-SNMP before 5.8. An unauthenticated attacker can send a crafted UDP packet that crashes the affected SNMP instance. This does not indicate data theft or system takeover, but it can disrupt monitoring and management services.

Executive priority

Prioritize remediation for externally reachable or business-critical SNMP services. The impact is availability disruption, not confirmed compromise, but monitoring outages can impair incident response and operations.

Technical view

The issue is a NULL pointer exception in snmp_oid_compare within snmplib/snmp_api.c. The CVSS 3.1 vector is network, low complexity, no privileges, no user interaction, with high availability impact only. The provided sources identify Net-SNMP before 5.8 as affected.

Likely exposure

Exposure is most relevant where Net-SNMP before 5.8 or vendor products bundling vulnerable Net-SNMP are reachable over UDP from untrusted networks. SNMP services exposed beyond management networks are higher priority.

Exploitation context

The CVE states unauthenticated remote crash via crafted UDP packet. CISA KEV status is false in the bundle, and no provided source proves active exploitation. A public remote DoS write-up is referenced, so defenders should treat details as publicly known.

Researcher notes

The bundle identifies CWE-476 and two SourceForge code references, suggesting a null-pointer handling fix path. Product scope beyond Net-SNMP before 5.8 is incomplete here; downstream exposure should be validated through vendor advisories rather than inferred.

Mitigation direction

  • Upgrade Net-SNMP to 5.8 or a vendor-fixed package where available.
  • Check NetApp, Oracle, and other vendor advisories for bundled Net-SNMP fixes.
  • Restrict SNMP UDP access to trusted management networks only.
  • Disable unnecessary SNMP services on internet-facing or untrusted interfaces.
  • Monitor for unexpected SNMP daemon crashes and restart loops.

Validation and detection

  • Inventory hosts and appliances running Net-SNMP or bundled SNMP services.
  • Confirm Net-SNMP versions are 5.8 or vendor-patched builds.
  • Review firewall rules for SNMP UDP exposure from untrusted networks.
  • Check service logs for crashes around SNMP packet handling.
  • Verify vendor advisories for affected downstream products before closure.
Prepared
Confidence
high
Sources
7

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cwe · low confidence lookup

CWE-476: Exact CWE lookup

Use the exact CWE identifier as the starting point before reviewing related ATT&CK behavior. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.

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cve · low confidence lookup

CVE-2018-18066 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

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Vulnerability profileCVE Program record
Severity
High
CVSS
7.5 (3.1)
Known Exploited
No
Published

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

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
0Timeline events
0ADP providers
6Source links

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
7.5CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

7.5High
CVSS 3.1 vector shape for CVE-2018-18066Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

CWE-476

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.

CWE-476 · source CWE mapping

NULL Pointer Dereference

NULL Pointer Dereference represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.

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