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CVE Record

CVE-2026-86510: D-Link DIR-822A L2TP Control Message tunnel_set_params out-of-bounds write

A vulnerability has been found in D-Link DIR-822A A_101. Affected is the function tunnel_set_params of the component L2TP Control Message Parser. Such manipulation leads to out-of-bounds write. The attack can be launched remotely. The exploit has been disclosed to the public and may be used.

CriticalCVSS 9.9Not KEV-listedUpdated
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Glexia's TakeAutomated analysiscritical

Security readout for executives and security teams

Plain-English summary

D-Link DIR-822A routers running firmware A_101 contain a critical memory-corruption flaw in L2TP message handling. A remote attacker with low-level privileges could potentially disrupt the router or compromise its confidentiality and integrity. Public exploit information exists, increasing urgency, but the supplied sources do not establish active exploitation.

Executive priority

Treat as an urgent network-edge risk. Identify affected routers immediately, reduce service exposure, and obtain vendor remediation guidance. Public technical details raise the likelihood of attempted exploitation, while the potential impact includes compromise or outage. Do not assume active exploitation solely from disclosure.

Technical view

The tunnel_set_params function in the L2TP Control Message Parser can perform an out-of-bounds write when processing manipulated input. CVSS 3.1 rates it 9.9 because exploitation is network-accessible, low complexity, requires low privileges, needs no user interaction, and may affect confidentiality, integrity, and availability beyond the vulnerable component.

Likely exposure

Exposure is limited to D-Link DIR-822A hardware running firmware A_101. Risk is greatest where the vulnerable L2TP functionality is reachable by untrusted networks or accounts. The supplied evidence does not identify other models, firmware versions, default exposure, or the exact privileges required.

Exploitation context

A technical disclosure and exploit reference are public, and VulDB states that exploitation may be possible. However, the CVE is not listed as KEV in the supplied bundle, and no cited source confirms attacks in the wild. Treat public disclosure as elevated opportunity, not proof of active exploitation.

Researcher notes

The supplied record maps the issue to CWE-119 and CWE-787 and reports a changed-scope CVSS vector with low privileges required. Important unknowns include vulnerable code reachability, authentication context, reliable impact, vendor patch status, and real-world exploitation. Testing should remain authorized and non-disruptive because malformed input may crash or corrupt the device.

Mitigation direction

  • Inventory DIR-822A devices and identify any running firmware A_101.
  • Check D-Link guidance for patched firmware or an approved replacement path.
  • Restrict access to L2TP services and management interfaces to trusted networks and accounts.
  • Disable unnecessary affected functionality if operationally safe and supported by vendor guidance.
  • Prioritize replacement if no supported remediation is available.

Validation and detection

  • Confirm device model and installed firmware through trusted inventory or administrative records.
  • Determine whether L2TP functionality is enabled and reachable from untrusted networks.
  • Review access controls for accounts permitted to interact with the affected service.
  • Check D-Link publications for a remediation specifically covering CVE-2026-86510.
  • Monitor for abnormal L2TP control traffic, crashes, or unexplained configuration changes.
Prepared
Confidence
medium
Sources
6

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-119: 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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cwe · low confidence lookup

CWE-787: 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.

Open ATT&CK lookup
cve · low confidence lookup

CVE-2026-86510 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
Critical
CVSS
9.9 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:P/RL:X/RC:R

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.

4CVSS vectors
6Timeline events
1ADP providers
7Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: pocAutomatable: noTechnical Impact: total

CVSS vector scores

4 official scores

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
9.9CVSS 3.1CriticalCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:P/RL:X/RC:R3.16VulDB
9.9CVSS 3.0CriticalCVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:P/RL:X/RC:R3.16VulDB
9.4CVSS 4.0CriticalCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:P——VulDB
9CVSS 2.0CriticalAV:N/AC:L/Au:S/C:C/I:C/A:C/E:POC/RL:ND/RC:UR810VulDB

Vulnerability scoring details

Base CVSS 4.0 score

9.4Critical
CVSS 4.0 vector shape for CVE-2026-86510Attack VectorAttack ComplexityAttack RequirementsPrivileges RequiredUser InteractionVS ConfidentialityVS IntegrityVS AvailabilitySS ConfidentialitySS IntegritySS Availability

Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:P

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Attack Requirements
NonePresent
Privileges Required
NoneLowHigh
User Interaction
NonePassiveActive
VS Confidentiality
HighLowNone
VS Integrity
HighLowNone
VS Availability
HighLowNone
SS Confidentiality
HighLowNone
SS Integrity
HighLowNone
SS Availability
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. Source timelineVulDB

    Advisory disclosed

  2. Source timelineVulDB

    VulDB entry created

  3. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  4. Source timelineVulDB

    VulDB entry last update

  5. CVE publishedCVE Program

    The CVE record was published.

  6. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
D-LinkDIR-822AA_101Listed
Weakness

CWE details

CWE-119CWE-787

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