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CVE-2021-29296: Null Pointer Dereference vulnerability in D-Link DIR-825 2.10b02, which could let a remote malicious user c...

Null Pointer Dereference vulnerability in D-Link DIR-825 2.10b02, which could let a remote malicious user cause a denial of service. The vulnerability could be triggered by sending an HTTP request with URL /vct_wan; the sbin/httpd would invoke the strchr function and take NULL as a first argument, which finally leads to the segmentation fault. NOTE: The DIR-825 and all hardware revisions is considered End of Life and as such this issue will not be patched

UnknownCVSS not scoredNot KEV-listedUpdated
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Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2021-29296 is a denial-of-service flaw in D-Link DIR-825 firmware 2.10b02. A remote request can crash the router’s web service. D-Link considers DIR-825 hardware revisions end of life, so the source says this issue will not be patched.

Executive priority

Prioritize replacement or isolation if DIR-825 routers support business connectivity or are reachable from untrusted networks. The direct impact is service disruption, not documented data theft, but the lack of a vendor patch makes continued use a persistent operational risk.

Technical view

The flaw is a null pointer dereference in DIR-825 sbin/httpd. The vulnerable handler can call strchr with NULL as the first argument, causing a segmentation fault and denial of service. The bundle does not provide CVSS, CWE, authenticated-state requirements, or broader affected-version evidence beyond DIR-825 2.10b02 and the EOL note.

Likely exposure

Exposure is most relevant where D-Link DIR-825 devices, especially firmware 2.10b02, are still deployed and reachable over HTTP. Internet-facing or broadly reachable router web interfaces carry higher operational risk. Evidence for other D-Link products is not provided in the bundle.

Exploitation context

The source bundle says a remote malicious user could cause denial of service. It does not cite CISA KEV listing, active exploitation, public exploit use, or observed attacks. Exploitation status should therefore be treated as unconfirmed from the provided evidence.

Researcher notes

Evidence is limited. The CVE description identifies the vulnerable web daemon behavior and an HTTP-triggered crash condition, but omits CVSS, CWE, authentication context, and patch details. Avoid assuming code execution or active exploitation without additional cited evidence.

Mitigation direction

  • Identify and replace EOL D-Link DIR-825 devices where feasible.
  • Check D-Link’s advisory pages for any model-specific guidance.
  • Remove internet exposure to DIR-825 web management interfaces.
  • Restrict management access to trusted administrative networks only.
  • Monitor affected devices for unexpected web-service crashes or availability loss.

Validation and detection

  • Inventory networks for D-Link DIR-825 devices and firmware versions.
  • Confirm whether router HTTP management is reachable from untrusted networks.
  • Review asset records for DIR-825 hardware marked end of life.
  • Check logs or uptime indicators for recurring web-service crashes.
  • Document compensating controls where replacement cannot happen immediately.
Prepared
Confidence
medium
Sources
4

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

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CVE-2021-29296 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
3Source 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.