VariantDraft

CWE-180Incorrect Behavior Order: Validate Before Canonicalize

Category: other

Description

The product validates input before it is canonicalized, which prevents the product from detecting data that becomes invalid after the canonicalization step. This can be used by an attacker to bypass the validation and launch attacks that expose weaknesses that would otherwise be prevented, such as injection.

Common consequences· 1

  • Access Control — Bypass Protection Mechanism

Potential mitigations· 1

  • [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· 6

CAPEC-267CAPEC-3CAPEC-71CAPEC-78CAPEC-79CAPEC-80

References

  1. https://cwe.mitre.org/data/definitions/180.html

Exploits (incoming)6

TypeTargetConfidenceTier
AttackPatternUsing Leading 'Ghost' Character Sequences to Bypass Input Filterscapec-3100%live
AttackPatternUsing Unicode Encoding to Bypass Validation Logiccapec-71100%live
AttackPatternUsing Slashes in Alternate Encodingcapec-79100%live
AttackPatternUsing Escaped Slashes in Alternate Encodingcapec-78100%live
AttackPatternLeverage Alternate Encodingcapec-267100%live
AttackPatternUsing UTF-8 Encoding to Bypass Validation Logiccapec-80100%live

(incoming)3

TypeTargetConfidenceTier
VulnerabilityCVE-2026-24895cve-2026-248950%live
VulnerabilityCVE-2026-27590cve-2026-275900%live
VulnerabilityCVE-2026-34475cve-2026-344750%live

Related by meaning· 6

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

CWE
Incorrect Behavior Order: Early Validation
CWE
Incorrect Behavior Order: Validate Before Filter
CWE
Improper Neutralization of Leading Special Elements
CWE
Improper Neutralization of Multiple Leading Special Elements
CWE
Improper Neutralization of Internal Special Elements
CWE
Deserialization of Untrusted Data
Sourced from MITRE CWE 4.20. Curated for EU compliance use cases by Adam Lundqvist, Founder at SQUR.