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CVE Record

CVE-2018-20812: An information exposure issue where IPv6 DNS traffic would be sent outside of the VPN tunnel (when Traffic...

An information exposure issue where IPv6 DNS traffic would be sent outside of the VPN tunnel (when Traffic Enforcement was enabled) exists in Pulse Secure Pulse Secure Desktop 9.0R1 and below. This is applicable only to dual-stack (IPv4/IPv6) endpoints.

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

This vulnerability can cause some Pulse Secure Desktop VPN users to leak IPv6 DNS lookups outside the VPN tunnel. That can reveal which domains a user is trying to reach, even when the VPN’s Traffic Enforcement feature is enabled. The source only names dual-stack endpoints running Pulse Secure Desktop 9.0R1 and below.

Executive priority

Treat this as a targeted privacy and policy-enforcement issue. It can undermine VPN confidentiality expectations, especially for remote users in sensitive environments, but the provided evidence does not support emergency response language. Prioritize verification and vendor-guided remediation for affected client populations.

Technical view

CVE-2018-20812 is an information exposure issue in Pulse Secure Desktop 9.0R1 and earlier. On endpoints with both IPv4 and IPv6 enabled, IPv6 DNS traffic may bypass the VPN tunnel despite Traffic Enforcement. The provided sources do not include CVSS, CWE, exploit details, or fixed-version text.

Likely exposure

Exposure is likely limited to dual-stack IPv4/IPv6 endpoints using Pulse Secure Desktop 9.0R1 or below with Traffic Enforcement enabled. Organizations without Pulse Secure Desktop, without affected versions, or without IPv6-capable endpoints are less likely to be affected based on the source bundle.

Exploitation context

The source bundle does not report active exploitation, and the CVE is not listed as CISA KEV. The practical risk is DNS metadata exposure, not direct code execution. Evidence about exploitability, prerequisites beyond dual-stack endpoints, and attacker positioning is incomplete.

Researcher notes

Key missing details are CVSS scoring, exact patched releases, and vendor remediation text. Analysis should stay constrained to the described DNS leak condition. Validate by configuration and network telemetry, not by offensive reproduction. Do not generalize this to all Pulse Secure products.

Mitigation direction

  • Review Pulse Secure advisory SA43877 for vendor-stated fixed versions or workarounds.
  • Inventory Pulse Secure Desktop versions and prioritize 9.0R1 and below.
  • Assess whether affected endpoints use dual-stack IPv4/IPv6 networking.
  • Apply vendor-supported updates or configuration changes once confirmed.
  • Monitor DNS egress paths for VPN clients until remediation is complete.

Validation and detection

  • Confirm whether Pulse Secure Desktop 9.0R1 or below is deployed.
  • Identify VPN clients with both IPv4 and IPv6 enabled.
  • Review Traffic Enforcement settings on affected client profiles.
  • Check whether VPN client DNS queries leave expected tunnel resolvers.
  • Document exceptions where IPv6 is disabled or unsupported.
Prepared
Confidence
medium
Sources
3

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

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CVE-2018-20812 mapping review

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Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
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.

0CVSS vectors
0Timeline events
0ADP providers
2Source links

CVSS and timeline data

No CVSS vectors or timeline events were available in the normalized CVE source material.

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
n/an/an/aListed
Weakness

CWE details

No CWE listed

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