CVE-2021-21369
In Besu before version 1.5.1 there is a denial-of-service vulnerability involving the HTTP JSON-RPC API service.
Does this matter?
Lower severity and a low EPSS score (1.67%). Track it; it rarely justifies an emergency change on its own.
Description
Hyperledger Besu is an open-source, MainNet compatible, Ethereum client written in Java. In Besu before version 1.5.1 there is a denial-of-service vulnerability involving the HTTP JSON-RPC API service. If username and password authentication is enabled for the HTTP JSON-RPC API service, then prior to making any requests to an API endpoint the requestor must use the login endpoint to obtain a JSON web token (JWT) using their credentials. A single user can readily overload the login endpoint with invalid requests (incorrect password). As the supplied password is checked for validity on the main vertx event loop and takes a relatively long time this can cause the processing of other valid requests to fail. A valid username is required for this vulnerability to be exposed. This has been fixed in version 1.5.1.
- CVSS 3.1
- 6.5 MEDIUMCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 1.67% probability · 77th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-400
- Affected
- linuxfoundation/besu
- Source
- security-advisories@github.com
EPSS 1.7% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
- https://github.com/hyperledger/besu/blob/master/CHANGELOG.md#151Release Notes, Third Party Advisory
- https://github.com/hyperledger/besu/commit/06e35a58c07a30c0fbdc0aae45a3e8b06b53c022Patch, Third Party Advisory
- https://github.com/hyperledger/besu/pull/1144Patch, Third Party Advisory
- https://github.com/hyperledger/besu/security/advisories/GHSA-qgfj-mjpc-7w3qThird Party Advisory
- https://github.com/hyperledger/besu/blob/master/CHANGELOG.md#151Release Notes, Third Party Advisory
- https://github.com/hyperledger/besu/commit/06e35a58c07a30c0fbdc0aae45a3e8b06b53c022Patch, Third Party Advisory
- https://github.com/hyperledger/besu/pull/1144Patch, Third Party Advisory
- https://github.com/hyperledger/besu/security/advisories/GHSA-qgfj-mjpc-7w3qThird Party Advisory
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.