CVE intelligence and bounded remediation

CVE-2020-26174 — Tangro Business Workflow security vulnerability

High CVSS 8.8

tangro Business Workflow before 1.18.1 requests a list of allowed filetypes from the server and restricts uploads to the filetypes contained in this list. However, this restriction is enforced in the browser (client-side) and can be circumvented. This allows an attacker to upload any file as an attachment to a workitem.

Severity
High
CVSS
8.8 (3.1)
Published
2020-12-18
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-434

Affected products

  • tangro / business_workflow

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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