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

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.

Published: 2024-11-18 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2021-1379 is rated Low Risk (34.3/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.32%). Mandatory action: Monitor for updates and reassess as exploit intelligence or EPSS changes.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-1379

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.05% 0.32% +0.26%
2 2025-06-24 0.04% 0.05% +0.01%
3 2025-03-30 0.04%

Full EPSS history (5 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-1379

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.5 3.1 MEDIUM
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:A)
Attacker has to be nearby on the network—same office, same link, that vibe—not the whole wide internet.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
2.8 3.6 [email protected]

Weakness enumeration for CVE-2021-1379

Affected software / configurations for CVE-2021-1379

Vendor Product Version Raw CPE
cisco ip_conference_phone_7832_firmware < 12.8\(1\) cpe:2.3:o:cisco:ip_conference_phone_7832_firmware:*:*:*:*:*:*:*:*
cisco ip_conference_phone_7832_firmware 12.8\(1\) cpe:2.3:o:cisco:ip_conference_phone_7832_firmware:12.8\(1\):-:*:*:*:*:*:*
cisco ip_conference_phone_7832_with_multiplatform_firmware < 11.3\(2\) cpe:2.3:o:cisco:ip_conference_phone_7832_with_multiplatform_firmware:*:*:*:*:*:*:*:*
cisco ip_conference_phone_8832_firmware < 12.8\(1\) cpe:2.3:o:cisco:ip_conference_phone_8832_firmware:*:*:*:*:*:*:*:*
cisco ip_conference_phone_8832_firmware 12.8\(1\) cpe:2.3:o:cisco:ip_conference_phone_8832_firmware:12.8\(1\):-:*:*:*:*:*:*
cisco ip_conference_phone_8832_with_multiplatform_firmware < 11.3\(2\) cpe:2.3:o:cisco:ip_conference_phone_8832_with_multiplatform_firmware:*:*:*:*:*:*:*:*
cisco ip_phone_6821_with_multiplatform_firmware < 11.3\(2\) cpe:2.3:o:cisco:ip_phone_6821_with_multiplatform_firmware:*:*:*:*:*:*:*:*
cisco ip_phone_6841_with_multiplatform_firmware < 11.3\(2\) cpe:2.3:o:cisco:ip_phone_6841_with_multiplatform_firmware:*:*:*:*:*:*:*:*
cisco ip_phone_6851_with_multiplatform_firmware < 11.3\(2\) cpe:2.3:o:cisco:ip_phone_6851_with_multiplatform_firmware:*:*:*:*:*:*:*:*
cisco ip_phone_6861_with_multiplatform_firmware < 11.3\(2\) cpe:2.3:o:cisco:ip_phone_6861_with_multiplatform_firmware:*:*:*:*:*:*:*:*
cisco ip_phone_6871_with_multiplatform_firmware < 11.3\(2\) cpe:2.3:o:cisco:ip_phone_6871_with_multiplatform_firmware:*:*:*:*:*:*:*:*
cisco ip_phone_7811_firmware < 12.8\(1\) cpe:2.3:o:cisco:ip_phone_7811_firmware:*:*:*:*:*:*:*:*
cisco ip_phone_7811_firmware 12.8\(1\) cpe:2.3:o:cisco:ip_phone_7811_firmware:12.8\(1\):-:*:*:*:*:*:*
cisco ip_phone_7811_with_multiplatform_firmware < 11.3\(2\) cpe:2.3:o:cisco:ip_phone_7811_with_multiplatform_firmware:*:*:*:*:*:*:*:*
cisco ip_phone_7821_firmware < 12.8\(1\) cpe:2.3:o:cisco:ip_phone_7821_firmware:*:*:*:*:*:*:*:*
cisco ip_phone_7821_firmware 12.8\(1\) cpe:2.3:o:cisco:ip_phone_7821_firmware:12.8\(1\):-:*:*:*:*:*:*
cisco ip_phone_7821_with_multiplatform_firmware < 11.3\(2\) cpe:2.3:o:cisco:ip_phone_7821_with_multiplatform_firmware:*:*:*:*:*:*:*:*
cisco ip_phone_7841_firmware < 12.8\(1\) cpe:2.3:o:cisco:ip_phone_7841_firmware:*:*:*:*:*:*:*:*
cisco ip_phone_7841_firmware 12.8\(1\) cpe:2.3:o:cisco:ip_phone_7841_firmware:12.8\(1\):-:*:*:*:*:*:*
cisco ip_phone_7841_with_multiplatform_firmware < 11.3\(2\) cpe:2.3:o:cisco:ip_phone_7841_with_multiplatform_firmware:*:*:*:*:*:*:*:*
cisco ip_phone_7861_firmware < 12.8\(1\) cpe:2.3:o:cisco:ip_phone_7861_firmware:*:*:*:*:*:*:*:*
cisco ip_phone_7861_firmware 12.8\(1\) cpe:2.3:o:cisco:ip_phone_7861_firmware:12.8\(1\):-:*:*:*:*:*:*
cisco ip_phone_7861_with_multiplatform_firmware < 11.3\(2\) cpe:2.3:o:cisco:ip_phone_7861_with_multiplatform_firmware:*:*:*:*:*:*:*:*
cisco ip_phone_8811_firmware < 12.8\(1\) cpe:2.3:o:cisco:ip_phone_8811_firmware:*:*:*:*:*:*:*:*
cisco ip_phone_8811_firmware 12.8\(1\) cpe:2.3:o:cisco:ip_phone_8811_firmware:12.8\(1\):-:*:*:*:*:*:*
cisco ip_phone_8811_with_multiplatform_firmware < 11.3\(2\) cpe:2.3:o:cisco:ip_phone_8811_with_multiplatform_firmware:*:*:*:*:*:*:*:*
cisco ip_phone_8841_firmware < 12.8\(1\) cpe:2.3:o:cisco:ip_phone_8841_firmware:*:*:*:*:*:*:*:*
cisco ip_phone_8841_firmware 12.8\(1\) cpe:2.3:o:cisco:ip_phone_8841_firmware:12.8\(1\):-:*:*:*:*:*:*
cisco ip_phone_8841_with_multiplatform_firmware < 11.3\(2\) cpe:2.3:o:cisco:ip_phone_8841_with_multiplatform_firmware:*:*:*:*:*:*:*:*
cisco ip_phone_8851_firmware < 12.8\(1\) cpe:2.3:o:cisco:ip_phone_8851_firmware:*:*:*:*:*:*:*:*
cisco ip_phone_8851_firmware 12.8\(1\) cpe:2.3:o:cisco:ip_phone_8851_firmware:12.8\(1\):-:*:*:*:*:*:*
cisco ip_phone_8851_with_multiplatform_firmware < 11.3\(2\) cpe:2.3:o:cisco:ip_phone_8851_with_multiplatform_firmware:*:*:*:*:*:*:*:*
cisco ip_phone_8861_firmware < 12.8\(1\) cpe:2.3:o:cisco:ip_phone_8861_firmware:*:*:*:*:*:*:*:*
cisco ip_phone_8861_firmware 12.8\(1\) cpe:2.3:o:cisco:ip_phone_8861_firmware:12.8\(1\):-:*:*:*:*:*:*
cisco ip_phone_8861_with_multiplatform_firmware < 11.3\(2\) cpe:2.3:o:cisco:ip_phone_8861_with_multiplatform_firmware:*:*:*:*:*:*:*:*
cisco ip_phone_8845_firmware < 12.8\(1\) cpe:2.3:o:cisco:ip_phone_8845_firmware:*:*:*:*:*:*:*:*
cisco ip_phone_8845_firmware 12.8\(1\) cpe:2.3:o:cisco:ip_phone_8845_firmware:12.8\(1\):-:*:*:*:*:*:*
cisco ip_phone_8845_with_multiplatform_firmware < 11.3\(2\) cpe:2.3:o:cisco:ip_phone_8845_with_multiplatform_firmware:*:*:*:*:*:*:*:*
cisco ip_phone_8865_firmware < 12.8\(1\) cpe:2.3:o:cisco:ip_phone_8865_firmware:*:*:*:*:*:*:*:*
cisco ip_phone_8865_firmware 12.8\(1\) cpe:2.3:o:cisco:ip_phone_8865_firmware:12.8\(1\):-:*:*:*:*:*:*
cisco ip_phone_8865_with_multiplatform_firmware < 11.3\(2\) cpe:2.3:o:cisco:ip_phone_8865_with_multiplatform_firmware:*:*:*:*:*:*:*:*
cisco unified_ip_conference_phone_8831_firmware < 10.3\(1\) cpe:2.3:o:cisco:unified_ip_conference_phone_8831_firmware:*:*:*:*:*:*:*:*
cisco unified_ip_conference_phone_8831_firmware 10.3\(1\) cpe:2.3:o:cisco:unified_ip_conference_phone_8831_firmware:10.3\(1\):-:*:*:*:*:*:*
cisco unified_ip_conference_phone_8831_firmware 10.3\(1\) cpe:2.3:o:cisco:unified_ip_conference_phone_8831_firmware:10.3\(1\):sr1:*:*:*:*:*:*
cisco unified_ip_conference_phone_8831_firmware 10.3\(1\) cpe:2.3:o:cisco:unified_ip_conference_phone_8831_firmware:10.3\(1\):sr2:*:*:*:*:*:*
cisco unified_ip_conference_phone_8831_firmware 10.3\(1\) cpe:2.3:o:cisco:unified_ip_conference_phone_8831_firmware:10.3\(1\):sr3:*:*:*:*:*:*
cisco unified_ip_conference_phone_8831_firmware 10.3\(1\) cpe:2.3:o:cisco:unified_ip_conference_phone_8831_firmware:10.3\(1\):sr4b:*:*:*:*:*:*
cisco unified_ip_conference_phone_8831_firmware 10.3\(1\) cpe:2.3:o:cisco:unified_ip_conference_phone_8831_firmware:10.3\(1\):sr6:*:*:*:*:*:*
cisco unified_ip_conference_phone_8831_for_third-party_call_control_firmware cpe:2.3:o:cisco:unified_ip_conference_phone_8831_for_third-party_call_control_firmware:-:*:*:*:*:*:*:*
cisco wireless_ip_phone_8821_firmware < 11.0\(6.6\) cpe:2.3:o:cisco:wireless_ip_phone_8821_firmware:*:*:*:*:*:*:*:*
cisco wireless_ip_phone_8821-ex_firmware < 11.0\(6.6\) cpe:2.3:o:cisco:wireless_ip_phone_8821-ex_firmware:*:*:*:*:*:*:*:*
cisco spa525g_firmware cpe:2.3:o:cisco:spa525g_firmware:-:*:*:*:*:*:*:*

References for CVE-2021-1379

cvelogic Threat Intelligence