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CVE-2021-21369

21
FAUCET Score

CVE-2021-21369 is a denial-of-service vulnerability affecting Hyperledger Besu versions prior to 1.5.1, specifically within its HTTP JSON-RPC API service. An authenticated attacker with a valid username can overload the login endpoint with invalid password attempts, causing legitimate requests to fail due to inefficient password validation on the main event loop. This vulnerability has a CVSS score of 6.5 (Medium), indicating a network-based attack with low complexity, requiring low privileges, and resulting in high availability impact. There is currently no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
< 1.5.1CPE matchmatch criteria
cpe:2.3:a:linuxfoundation:besu:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

6.5MEDIUM

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
NONE
Availability Impact
HIGH
Exploitability Score
2.8
Impact Score
3.6
CvssVersion
3.1

Exploit Intelligence

EPSS Score
1.50%
Probability of exploitation in next 30 days
EPSS Percentile
71.7%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0150 is in the 85th percentile among its peer group of 21,974 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.1 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.0 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (1)

github_advisorypatch availablevia nvd_reference
View patch

References

github.com / hyperledger/besu/blob/master/CHANGELOG.md
Release NotesThird Party Advisory
github.com / hyperledger/besu/commit/06e35a58c07a30c0fbdc0aae45a3e8b06b53c022
PatchThird Party Advisory
github.com / hyperledger/besu/pull/1144
PatchThird Party Advisory
github.com / hyperledger/besu/security/advisories/GHSA-qgfj-mjpc-7w3q
Third Party Advisory