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Home/CWEs/CWE-86
Common Weakness Enumeration

CWE-86: Improper Neutralization of Invalid Characters in Identifiers in Web Pages

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The product does not neutralize or incorrectly neutralizes invalid characters or byte sequences in the middle of tag names, URI schemes, and other identifiers.

Abstraction
Variant
Related CVEs
0

▪References & documentation

https://cwe.mitre.org/data/definitions/86.htmlNVD CWE listing

▪ How attackers exploit CWE-86

MITRE ATT&CK techniques associated with this weakness class (mapped via MITRE CAPEC). A vulnerability of this type could let an adversary carry out:

T1036MasqueradingstealthT1082System Information Discoverydiscovery

Step-by-step: how CWE-86 gets exploited

A stage-by-stage walkthrough of the attack, mapped to the real MITRE ATT&CK tactics for this weakness — what the attacker is trying to do, what's at risk (what can be stolen or damaged), and how you defend. Understanding the playbook is how you shut it down.

  1. 1
    Discoverydiscovery

    Map what else is reachable — hosts, services, data stores, and accounts.

    At risk / what's stolen

    Internal topology, service inventory, and data locations the attacker enumerates.

    How you defend

▪ Related CVEs

No CVEs in the Gold index currently reference CWE-86. New matches appear here as the crawler indexes them.

Network segmentation and detection of unusual internal scanning.

This is a defensive, conceptual walkthrough for education — stages reflect MITRE ATT&CK tactics associated with this weakness class, not a working exploit. Not every attack uses every stage.