OWASPASVS 5.0 requirement

ASVS-V3.5.5 Messages received by the postmessage interface are discarded if the origin of the message is not trusted, or if the syntax of the message…

L2 Published 2025 Official page ↗
Standard
OWASP ASVS 5.0
Chapter
V3 Web Frontend Security
Section
V3.5 Browser Origin Separation
Level
L2 (requirement applies from this verification level up)

Requirement

Verify that messages received by the postMessage interface are discarded if the origin of the message is not trusted, or if the syntax of the message is invalid.