CVE-2021-29296Network attack vector

Remote service crash via NULL pointer dereference

Published Aug 10, 2021 · Updated Aug 3, 2024

NULL pointer dereference in D-Link DIR-825 2.10b02 allows remote attackers to crash the router's HTTP service via /vct_wan. The /sbin/httpd handler passes NULL as the first argument to strchr while processing the crafted URL, causing a segmentation fault. No authentication or user interaction is required; the documented result is interruption of the embedded web service, not code execution or data access.

CVSS severity7.5
High
EPSS probability1.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL pointer dereference in D-Link DIR-825 2.10b02 allows remote attackers to crash the router's HTTP service via /vct_wan. The /sbin/httpd handler passes NULL as the first argument to strchr while processing the crafted URL, causing a segmentation fault. No authentication or user interaction is required; the documented result is interruption of the embedded web service, not code execution or data access.

The record

CVE
CVE-2021-29296
Published
Aug 10, 2021
Updated
Aug 3, 2024
Vendor
D-Link
Product
DIR-825
Classifications
CWE-476, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 10, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=2.10b02

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

D-Link · DIR-825version=2.10b02

Published CVSS scores

5.0NIST NVDAV:N/AC:L/Au:N/C:N/I:N/A:P
7.5NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-476NULL Pointer Dereference
T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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