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CVE Record

CVE-2021-23386: Remote Memory Exposure

This affects the package dns-packet before 5.2.2. It creates buffers with allocUnsafe and does not always fill them before forming network packets. This can expose internal application memory over unencrypted network when querying crafted invalid domain names.

HighCVSS 7.7Not KEV-listedUpdated
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Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

CVE-2021-23386 is a memory disclosure issue in dns-packet before 5.2.2. Under crafted invalid domain-name input, the library may send DNS packets containing leftover application memory. The main business risk is unintended leakage of sensitive process data over unencrypted network traffic.

Executive priority

Treat this as a high-priority dependency remediation when dns-packet is present in production services. It is not currently described as actively exploited in the provided sources, but memory exposure can create serious confidentiality risk.

Technical view

dns-packet used allocUnsafe buffers and did not always fully initialize them before network packet construction. The CVSS 3.1 score is 7.7, with high confidentiality impact, high attack complexity, low privileges required, no user interaction, and changed scope. Affected versions are before 5.2.2.

Likely exposure

Exposure is most likely in Node.js or packaged WebJars/npm applications that depend on dns-packet versions before 5.2.2 and generate DNS packets from untrusted or externally influenced domain names.

Exploitation context

The source bundle does not show CISA KEV listing or cited active exploitation. The vulnerability requires crafted invalid domain names and has high attack complexity, but successful exploitation could disclose internal application memory.

Researcher notes

Focus validation on dependency reachability and data sensitivity. The provided description ties exposure to packet construction from crafted invalid domain names and unencrypted network paths. Avoid assuming exploitability in every consumer without confirming the vulnerable code path is reachable.

Mitigation direction

  • Upgrade dns-packet to version 5.2.2 or later.
  • Refresh lockfiles and redeploy services that bundle the vulnerable dependency.
  • Check vendor guidance for transitive or WebJars/npm packaged uses.
  • Prefer encrypted network paths where DNS-related application traffic may expose sensitive data.

Validation and detection

  • Inventory direct and transitive dns-packet dependencies across Node.js projects.
  • Confirm deployed artifacts do not include dns-packet versions before 5.2.2.
  • Review SBOM and lockfile output for WebJars/npm variants.
  • Verify tests cover invalid domain-name handling without leaking uninitialized buffer data.
Prepared
Confidence
high
Sources
5

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-2021-23386 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
7.7 (3.1)
Known Exploited
No
Published

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

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
5Source 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
7.7CVSS 3.1HighCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:L/A:L1.85.3Primary CVE score

Vulnerability scoring details

Base CVSS 3.1 score

7.7High
CVSS 3.1 vector shape for CVE-2021-23386Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

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

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/adns-packetunspecifiedListed
Weakness

CWE details

No CWE listed

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