CVE-2021-1521

Unexpected reboot via unchecked discovery protocol message

Published May 6, 2021 · Updated Nov 8, 2024

Denial of service in Cisco Discovery Protocol handling on Cisco 8000 Series IP Cameras before 1.0.9-11 allows attackers to force a reboot. The implementation omits required bounds checks while processing a crafted Cisco Discovery Protocol message, allowing malformed Layer 2 data to trigger the reload. Cisco Discovery Protocol must be enabled, and the attacker must share the camera's Layer 2 broadcast domain; the bounded consequence is a service interruption during the reboot.

CVSS severity6.5
Medium
EPSS probability0.40%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Cisco Discovery Protocol handling on Cisco 8000 Series IP Cameras before 1.0.9-11 allows attackers to force a reboot. The implementation omits required bounds checks while processing a crafted Cisco Discovery Protocol message, allowing malformed Layer 2 data to trigger the reload. Cisco Discovery Protocol must be enabled, and the attacker must share the camera's Layer 2 broadcast domain; the bounded consequence is a service interruption during the reboot.

The record

CVE
CVE-2021-1521
Published
May 6, 2021
Updated
Nov 8, 2024
Vendor
ClamAV
Product
Cisco Video Surveillance 8000 Series IP Cameras
Classifications
CWE-119, T1499.004
Attack vector
adjacent
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 6, 2021CVE publishedPublication date reported by the CVE source.
  2. Nov 8, 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?

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  1. Affected versionversion=n/a

What conditions does exploitation require?

Attack vectoradjacent
Required privilegesunauthenticated

What is affected?

ClamAV · Cisco Video Surveillance 8000 Series IP Camerasversion=n/a

Published CVSS scores

6.5Cisco PSIRTCVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:X/RL:X/RC:X

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)
Vectoradjacent
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-119Improper Restriction of Operations within the Bounds of a Memory Buffer
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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