VariantDraft

CWE-177Improper Handling of URL Encoding (Hex Encoding)

Category: other

Description

The product does not properly handle when all or part of an input has been URL encoded.

Common consequences· 1

  • Integrity — Unexpected State

Potential mitigations· 3

  • [Architecture and Design]Avoid making decisions based on names of resources (e.g. files) if those resources can have alternate names.
  • [Implementation]
  • [Implementation]Inputs should be decoded and canonicalized to the application's current internal representation before being validated (CWE-180). Make sure that the application does not decode the same input twice (CWE-174). Such errors could be used to bypass allowlist validation schemes by introducing dangerous inputs after they have been checked.

Related CAPEC attack patterns· 4

CAPEC-120CAPEC-468CAPEC-64CAPEC-72

References

  1. https://cwe.mitre.org/data/definitions/177.html

Exploits (incoming)4

TypeTargetConfidenceTier
AttackPatternDouble Encodingcapec-120100%live
AttackPatternUsing Slashes and URL Encoding Combined to Bypass Validation Logiccapec-64100%live
AttackPatternURL Encodingcapec-72100%live
AttackPatternGeneric Cross-Browser Cross-Domain Theftcapec-468100%live

(incoming)3

TypeTargetConfidenceTier
VulnerabilityCVE-2026-22031cve-2026-220310%live
VulnerabilityCVE-2026-22037cve-2026-220370%live
VulnerabilityCVE-2026-29045cve-2026-290450%live

Related by meaning· 6

Nearest entities by semantic similarity across the cs-graph corpus.

CWE
Improper Handling of Unicode Encoding
CWE
Improper Handling of Invalid Use of Special Elements
CWE
Improper Handling of Alternate Encoding
CWE
Improper Encoding or Escaping of Output
CWE
Improper Handling of Mixed Encoding
CWE
Incorrect Regular Expression
Sourced from MITRE CWE 4.20. Curated for EU compliance use cases by Adam Lundqvist, Founder at SQUR.