kb/data/developer.mozilla.org/en-US/docs/Glossary/Replay_attack-0.md

title	chunk	source	category	tags	date_saved	instance
Replay attack - Glossary | MDN	1/3	https://developer.mozilla.org/en-US/docs/Glossary/Replay_attack	reference	web, html, css, javascript, documentation	2026-05-05T05:42:44.172313+00:00	kb-cron

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1. Glossary
2. Replay attack

Replay attack

In web security, a replay attack happens when an attacker intercepts a previously-sent message and resends it later to get the same credentials as the original message, potentially with a different payload or instruction. Replay attacks can be prevented by including a unique, single-use identifier with each message that the receiver can use to verify the authenticity of the transmission. This identifier can take the form of a session token or "number used only once" (nonce).

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• See also

See also

• Replay attack on Wikipedia.