CVE-2024-30172Network attack vector

Verification hang via unbounded Ed25519 scalar reduction

Published May 9, 2024 · Updated Nov 5, 2024

Denial of service in Bouncy Castle for Java 1.73 through 1.77 allows remote attackers to hang verification via crafted Ed25519 inputs. The Ed25519 implVerify path passes an attacker-derived scalar into Scalar25519.reduceBasisVar, whose reduction loop lacked an iteration bound and could fail to converge. Exposure requires an application to verify an attacker-supplied signature and public key; the resulting loop consumes the verification thread indefinitely.

CVSS severity6.9
Medium
EPSS probability0.75%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Denial of service in Bouncy Castle for Java 1.73 through 1.77 allows remote attackers to hang verification via crafted Ed25519 inputs. The Ed25519 implVerify path passes an attacker-derived scalar into Scalar25519.reduceBasisVar, whose reduction loop lacked an iteration bound and could fail to converge. Exposure requires an application to verify an attacker-supplied signature and public key; the resulting loop consumes the verification thread indefinitely.

The record

CVE
CVE-2024-30172
Published
May 9, 2024
Updated
Nov 5, 2024
Vendor
Legion of the Bouncy Castle Inc.
Product
Bouncy Castle for Java
Classifications
CWE-835, T1499
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 9, 2024CVE publishedPublication date reported by the CVE source.
  2. Nov 5, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <1.78

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Legion of the Bouncy Castle Inc. · Bouncy Castle for Javaversion=0 <1.78

Published CVSS scores

6.9GitHubCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
5.3GitHubCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-835Loop with Unreachable Exit Condition ('Infinite Loop')
T1499Endpoint Denial of Service

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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