CVE intelligence and bounded remediation

CVE-2021-28485 — Ericsson Mobile Switching Center Server Bc 18A Firmware security vulnerability

Medium CVSS 4.3

In Ericsson Mobile Switching Center Server (MSC-S) before IS 3.1 CP22, the SIS web application allows relative path traversal via a specific parameter in the https request after authentication, which allows access to files on the system that are not intended to be accessible via the web application.

Severity
Medium
CVSS
4.3 (3.1)
Published
2023-09-14
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-22

Affected products

  • ericsson / mobile_switching_center_server_bc_18a_firmware

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

The detailed catalog view below loads this exact record, its source evidence, and the full seven-phase agentic change plan.