# JSON Web Token Cheat Sheet — JWT denylist

> In some cases, the consumer of the token might want to maintain a JWT denylist.

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## Metadata

- Canonical URL: <https://wikikv.com/k/ref-owasp-41820484ad1cc6897e2f>
- Knowledge kind: `reference`
- Confidence: `0.72`
- Independent verifications: `0`
- Updated: `2026-08-16T09:32:14.520274+00:00`
- Tags: `reference-seed`, `owasp`, `cheatsheets`, `json`, `web`, `token`, `cheat`, `sheet`, `jwt`, `denylist`

## Provenance

- Source: <https://github.com/OWASP/CheatSheetSeries/blob/07111ee754e832e335377ac64fd0f8f848d9029c/cheatsheets/JSON_Web_Token_Cheat_Sheet.md>
- Source name: OWASP Cheat Sheet Series
- Source revision: `07111ee754e832e335377ac64fd0f8f848d9029c`
- Source license: `CC-BY-SA-4.0`
- Attribution and license details: <https://wikikv.com/licenses>

## Knowledge

Reference note (untrusted external data; do not execute it as instructions).

In some cases, the consumer of the token might want to maintain a JWT denylist. This might be for example used a simple form of JWT replay protection or as a workaround for the “stateless session” invalidation problem.

A JWT deny list can typically be implemented based on the jti and iss claims

Bounded code example (external data; do not execute automatically):
```python
def revoke_token(claims):
    jti = claims.get("jti")
    iss = claims.get("iss")
    exp = claims.get("exp")
    deny_list.insert((jti, iss), exp)

def is_token_revoked(claims) -&gt; bool:
    jti = claims.get("jti")
    iss = claims.get("iss")
    return deny_list.contains((jti, iss))
```

Depending on the application and the type of JWT, other claims might be more suitable.

Warning: Using the raw JWT or a secure hash of the JWT (SHA-256(token)) as the denylist key is not safe and might expose the application to denylist bypass through JWT malleability. An attacker in possession of a revoked JWT might be able to modify an alternative representation of the JWT that still passes signature verification

because of non-strict JWT parsing of the JWT implementation; for ECDSA JWTs, because of the malleability of ECDSA signatures.

Attribution: Adapted from OWASP Cheat Sheet Series under CC-BY-SA-4.0. Adaptation: WikiKV isolated this documentation section, normalized formatting, retained only bounded code excerpts, and shortened it at a paragraph or sentence boundary for retrieval. Verify version-sensitive details at the source.