CVE-2021-34711: Cisco IP Phone Software Arbitrary File Read Vulnerability

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.3% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-10-06 · updated 2026-06-17
Weakness: CWE-36

Description

A vulnerability in the debug shell of Cisco IP Phone software could allow an authenticated, local attacker to read any file on the device file system. This vulnerability is due to insufficient input validation. An attacker could exploit this vulnerability by providing crafted input to a debug shell command. A successful exploit could allow the attacker to read any file on the device file system.

Affected products

Cisco Ip Conference Phone 7832 Firmware: before 14.1\(1\) — fixed in 14.1\(1\)
Cisco Ip Conference Phone 8832 Firmware: before 14.1\(1\) — fixed in 14.1\(1\)
Cisco Ip Phone 7811 Firmware: before 14.1\(1\) — fixed in 14.1\(1\)
Cisco Ip Phone 7821 Firmware: before 14.1\(1\) — fixed in 14.1\(1\)
Cisco Ip Phone 7832 Firmware: before 14.1\(1\) — fixed in 14.1\(1\)
Cisco Ip Phone 7841 Firmware: before 14.1\(1\) — fixed in 14.1\(1\)
Cisco Ip Phone 7861 Firmware: before 14.1\(1\) — fixed in 14.1\(1\)
Cisco Ip Phone 8811 Firmware: before 14.1\(1\) — fixed in 14.1\(1\)
Cisco Ip Phone 8831 Firmware: before 14.1\(1\) — fixed in 14.1\(1\)
Cisco Ip Phone 8841 Firmware: before 14.1\(1\) — fixed in 14.1\(1\)
Cisco Ip Phone 8845 Firmware: before 14.1\(1\) — fixed in 14.1\(1\)
Cisco Ip Phone 8851 Firmware: before 14.1\(1\) — fixed in 14.1\(1\)
Cisco Ip Phone 8861 Firmware: before 14.1\(1\) — fixed in 14.1\(1\)
Cisco Ip Phone 8865 Firmware: before 14.1\(1\) — fixed in 14.1\(1\)
Cisco Ip Phones 8832 Firmware: before 14.1\(1\) — fixed in 14.1\(1\)
Cisco Wireless Ip Phone 8821 Firmware: before 11.0\(6\)sr2 — fixed in 11.0\(6\)sr2

How to fix

Upgrade to a fixed version: Cisco Ip Conference Phone 7832 Firmware 14.1\(1\); Cisco Ip Conference Phone 8832 Firmware 14.1\(1\); Cisco Ip Phone 7811 Firmware 14.1\(1\); Cisco Ip Phone 7821 Firmware 14.1\(1\); Cisco Ip Phone 7832 Firmware 14.1\(1\); Cisco Ip Phone 7841 Firmware 14.1\(1\); Cisco Ip Phone 7861 Firmware 14.1\(1\); Cisco Ip Phone 8811 Firmware 14.1\(1\); Cisco Ip Phone 8831 Firmware 14.1\(1\); Cisco Ip Phone 8841 Firmware 14.1\(1\); Cisco Ip Phone 8845 Firmware 14.1\(1\); Cisco Ip Phone 8851 Firmware 14.1\(1\). Check the vendor advisory for mitigations.

References

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