CVE intelligence and bounded remediation

CVE-2019-1681 — Cisco Ios Xr security vulnerability

High CVSS 7.5

A vulnerability in the TFTP service of Cisco Network Convergence System 1000 Series software could allow an unauthenticated, remote attacker to retrieve arbitrary files from the targeted device, possibly resulting in information disclosure. The vulnerability is due to improper validation of user-supplied input within TFTP requests processed by the affected software. An attacker could exploit this vulnerability by using directory traversal techniques in malicious requests sent to the TFTP service on a targeted device. An exploit could allow the attacker to retrieve arbitrary files from the targeted device, resulting in the disclosure of sensitive information. This vulnerability affects Cisco IOS XR Software releases prior to Release 6.5.2 for Cisco Network Convergence System 1000 Series devices when the TFTP service is enabled.

Severity
High
CVSS
7.5 (3.1)
Published
2019-02-21
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-200, CWE-22

Affected products

  • cisco / ios_xr

Matched remediation archetype

Path traversal, unsafe upload, and file handling

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

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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