CVE intelligence and bounded remediation

CVE-2021-42839 — Vice Webopac security vulnerability

High CVSS 9

Grand Vice info Co. webopac7 file upload function fails to filter special characters. While logging in with general user’s permission, remote attackers can upload malicious script and execute arbitrary code to control the system or interrupt services.

Severity
High
CVSS
9 (2.0)
Published
2021-11-15
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-434

Affected products

  • vice / webopac / 1.8.20160701
  • vice / webopac / 7.1.20160701

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.