CVE intelligence and bounded remediation

CVE-2019-1765 — Cisco Ip Phone 8821 Firmware security vulnerability

High CVSS 8.1

A vulnerability in the web-based management interface of Session Initiation Protocol (SIP) Software for Cisco IP Phone 8800 Series could allow an authenticated, remote attacker to write arbitrary files to the filesystem. The vulnerability is due to insufficient input validation and file-level permissions. An attacker could exploit this vulnerability by uploading invalid files to an affected device. A successful exploit could allow the attacker to write files in arbitrary locations on the filesystem. This vulnerability affects Cisco IP Phone 8800 Series products running a SIP Software release prior to 11.0(5) for Wireless IP Phone 8821 and 8821-EX; and 12.5(1)SR1 for the IP Conference Phone 8832 and the rest of the IP Phone 8800 Series.

Severity
High
CVSS
8.1 (3.0)
Published
2019-03-22
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-22

Affected products

  • cisco / ip_phone_8821_firmware
  • cisco / ip_phone_8821-ex_firmware
  • cisco / ip_conference_phone_8832_firmware
  • cisco / ip_phone_8800_firmware

Matched remediation archetype

Path traversal, unsafe upload, and file handling

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Check exposure

  • Trace untrusted filenames, archive entries, URLs, and path segments into read, write, include, extraction, and upload operations.
  • Identify filesystem roots, mount permissions, symbolic-link behavior, archive handling, and whether uploaded content is web-accessible or executable.
  • Review canonicalization and containment checks across supported operating systems and storage backends.

Remediate safely

  • Generate server-side storage identifiers and resolve paths beneath a fixed root using filesystem-aware containment checks.
  • Reject absolute, parent-relative, alternate-separator, device, link, and archive entries that escape the intended root.
  • Store uploads outside executable or served paths, validate type and size, and use private atomic temporary files.

Authoritative sources

Complete CVE record and remediation plan

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