CVE intelligence and bounded remediation

CVE-2020-27643 — 1E Client security vulnerability

Medium CVSS 6.5

The %PROGRAMDATA%\1E\Client directory in 1E Client 5.0.0.745 and 4.1.0.267 allows remote authenticated users and local users to create and modify files in protected directories (where they would not normally have access to create or modify files) via the creation of a junction point to a system directory. This leads to partial privilege escalation.

Severity
Medium
CVSS
6.5 (3.1)
Published
2020-12-29
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-59

Affected products

  • 1e / client / 4.1.0.267
  • 1e / client / 5.0.0.745

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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