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CVE Record

CVE-2021-28841: Null Pointer Dereference vulnerability in TRENDnet TEW-755AP 1.11B03, TEW-755AP2KAC 1.11B03, TEW-821DAP2KAC...

Null Pointer Dereference vulnerability in TRENDnet TEW-755AP 1.11B03, TEW-755AP2KAC 1.11B03, TEW-821DAP2KAC 1.11B03, and TEW-825DAP 1.11B03, which could let a remote malicious user cause a denial of service by sending a POST request to apply_cgi via an action ping_test without a ping_ipaddr key.

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 make certain TRENDnet wireless access points crash or stop responding when they receive a malformed management request. The known impact is denial of service, not data theft or device takeover. Business urgency depends on whether the named models and firmware are still deployed and reachable from untrusted networks.

Executive priority

Treat this as a targeted availability risk for affected wireless infrastructure. Prioritize discovery and management-plane isolation first. Escalate if affected devices support critical sites, are remotely reachable, or lack vendor-supported firmware updates.

Technical view

CVE-2021-28841 is a null pointer dereference in TRENDnet TEW-755AP, TEW-755AP2KAC, TEW-821DAP2KAC, and TEW-825DAP firmware 1.11B03. The CVE describes remote denial of service through a malformed POST request to a management CGI endpoint. No CVSS score, CWE mapping, or vendor remediation is included in the provided sources.

Likely exposure

Exposure appears limited to the listed TRENDnet access point models running firmware 1.11B03. Risk is higher where device management interfaces are reachable from user, guest, partner, or internet-facing networks. Evidence does not establish broader product impact.

Exploitation context

The source bundle does not show CISA KEV inclusion or active exploitation. Public details describe the vulnerable request condition, but the provided evidence does not confirm weaponized exploitation, exploit availability, authentication requirements, or crash recovery behavior.

Researcher notes

The provided CVE data names specific models and firmware but lacks CVSS, CWE, authentication context, patch status, and reliable exploitation telemetry. Validation should focus on asset confirmation and exposure review, not recreating the malformed request condition in production.

Mitigation direction

  • Inventory TRENDnet access points and confirm model and firmware versions.
  • Check TRENDnet support guidance for fixed firmware or official mitigations.
  • Restrict management interfaces to trusted administration networks only.
  • Block guest, user, and internet access to device administration services.
  • Replace unsupported affected devices if no vendor fix is available.

Validation and detection

  • Confirm whether any listed models run firmware 1.11B03.
  • Review network paths to each device management interface.
  • Check monitoring for unexplained access point crashes or reboots.
  • Verify management access controls from guest and user segments.
  • Document whether vendor guidance or firmware updates are available.
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-2021-28841 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.