Home/CWE/Improper Neutralization of Alternate XSS Syntax
Weakness

Improper Neutralization of Alternate XSS Syntax

CWE-87 · Variant · Draft

The product does not neutralize or incorrectly neutralizes user-controlled input for alternate script syntax.

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Weakness Relationships

Where this weakness sits in the CWE hierarchy. Walk up to broader classes or down to more specific variants.
Parent of this (broader)
ChildOfCWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
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Attack Patterns (CAPEC)

1
How adversaries exploit this weakness, per MITRE CAPEC.
CAPEC-199XSS Using Alternate Syntax
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CVEs With This Weakness

50
A sample of the 50 CVEs tagged with this weakness.
CVECVE-2026-45314
CVECVE-2026-42458
CVECVE-2026-42235
CVECVE-2026-40321
CVECVE-2026-35534
CVECVE-2026-34598
CVECVE-2026-33510
CVECVE-2026-33506
CVECVE-2026-27120
CVECVE-2026-22711
CVECVE-2025-8561
CVECVE-2025-65961
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Nuclei Scanner Templates

1
Open-source Nuclei templates that detect this weakness class - an actionable scan-for-it pivot. Licensed under the ProjectDiscovery / Nuclei terms.
mediumXWiki - Cross-Site Scripting
External lookups - second-class, for what we don’t hold ourselves
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