CVE-2024-20376Network attack vector

Device reload via malformed management request

Published May 1, 2024 · Updated Aug 1, 2024

Denial of service in Cisco IP Phone firmware allows remote attackers to reload devices through the web-based management interface. The interface insufficiently validates user-supplied data in a crafted web request before processing it, resulting in an out-of-bounds write. No authentication or user interaction is required; successful exploitation reboots the phone and interrupts its service.

CVSS severity7.5
High
EPSS probability0.88%
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 IP Phone firmware allows remote attackers to reload devices through the web-based management interface. The interface insufficiently validates user-supplied data in a crafted web request before processing it, resulting in an out-of-bounds write. No authentication or user interaction is required; successful exploitation reboots the phone and interrupts its service.

The record

CVE
CVE-2024-20376
Published
May 1, 2024
Updated
Aug 1, 2024
Vendor
ClamAV
Product
Cisco IP Phone 6821 with Multiplatform Firmware
Classifications
CWE-787, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

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

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=0 <=12.0.4

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

ClamAV · Cisco IP Phone 6821 with Multiplatform Firmwareversion=0 <=12.0.4
ClamAV · Cisco IP Phone 6861 with Multiplatform Firmwareversion=0 <=12.0.4
ClamAV · Cisco IP Phone 7811 with Multiplatform Firmwareversion=0 <=12.0.4
ClamAV · Cisco IP Phone 6851 with Multiplatform Firmwareversion=0 <=12.0.4
ClamAV · Cisco IP Phone 8800 Series with Multiplatform Firmwareversion=0 <=12.0.4
ClamAV · Cisco PhoneOSversion=1.0.1; version=2.0.1; version=2.1.1; version=2.3.1
ClamAV · Cisco IP Phone 6841 with Multiplatform Firmwareversion=0 <=12.0.4
ClamAV · Cisco IP Phone 7861 with Multiplatform Firmwareversion=0 <=12.0.4
ClamAV · Cisco IP DECT 6825 with Multiplatform Firmwareversion=0 <=12.0.4
ClamAV · Cisco IP Phone 7841 with Multiplatform Firmwareversion=0 <=12.0.4
ClamAV · Cisco IP Phone 7821 with Multiplatform Firmwareversion=0 <=12.0.4
ClamAV · Cisco Video Phone 8875 Firmwareversion=0 <=12.0.4
ClamAV · Cisco IP Phone 6871 with Multiplatform Firmwareversion=0 <=12.0.4
ClamAV · Cisco IP Phones with Multiplatform Firmwareversion=11.0.0; version=11.0.1; version=11.0.1 MSR1-1; version=11.0.2; version=11.1.1; version=11.1.1 MSR1-1; version=11.1.1 MSR2-1; version=11.1.2; version=11.1.2 MSR1-1; version=11.1.2 MSR3-1; version=11.2.1; version=11.2.2; version=11.2.3; version=11.2.3 MSR1-1; version=11.2.4; version=11.3.1; version=11-3-1MPPSR4UPG; version=11.3.1 MSR1-3; version=11.3.1 MSR2-6; version=11-3-1MSR2UPG; version=11.3.1 MSR3-3; version=11.3.1 MSR4-1; version=11.3.2; version=11.3.3; version=11.3.3 MSR1; version=11.3.3 MSR2; version=11.3.4; version=11.3.5; version=11.3.6; version=11.3.6SR1; version=11.3.7; version=11.3.7SR1; version=11.3.7SR2; version=12.0.1; version=12.0.2; version=12.0.3; version=12.0.3SR1; version=12.0.4; version=4.5; version=4.6 MSR1; version=4.7.1; version=4.8.1; version=4.8.1 SR1; version=5.0.1; version=5.1.1; version=5.1.2; version=5.1(2)SR1

Published CVSS scores

7.5Cisco Systems, Inc.CVSS: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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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-787Out-of-bounds Write
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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