CVE-2024-29857 in Bouncy Castle
Summary
by MITRE • 05/14/2024
An issue was discovered in Bouncy Castle Java Cryptography APIs before BC 1.78. Importing an EC certificate with crafted F2m parameters can lead to excessive CPU consumption during the evaluation of the curve parameters.
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Analysis
by VulDB Data Team • 08/18/2025
The vulnerability CVE-2024-29857 represents a significant performance degradation issue within the Bouncy Castle Java Cryptography APIs ecosystem, specifically affecting versions prior to BC 1.78. This flaw manifests when the system processes EC certificates containing deliberately crafted F2m parameters that cause excessive CPU consumption during curve parameter evaluation. The issue stems from inadequate validation and optimization within the elliptic curve cryptographic processing routines, creating a potential denial of service scenario where maliciously constructed certificates can trigger disproportionate computational overhead.
The technical root cause of this vulnerability lies in the insufficient parameter validation mechanisms within the Bouncy Castle implementation of elliptic curve cryptography operations. When processing EC certificates with F2m (finite field of characteristic 2) parameters, the cryptographic library fails to properly validate the mathematical properties of these parameters before attempting computationally intensive operations. This allows attackers to craft certificates containing malformed or specially constructed F2m parameters that force the system to perform excessive mathematical computations during the curve validation phase. The vulnerability operates at the level of cryptographic algorithm implementation where the library processes public key certificates, making it particularly dangerous in environments where certificate validation occurs frequently.
The operational impact of CVE-2024-29857 extends beyond simple performance degradation to potentially enabling denial of service attacks against systems relying on Bouncy Castle for cryptographic operations. Attackers can exploit this vulnerability by presenting maliciously crafted EC certificates to systems using vulnerable Bouncy Castle versions, causing the cryptographic library to consume excessive CPU resources during certificate validation. This can lead to system resource exhaustion, application slowdowns, or complete service unavailability, particularly affecting systems that process large volumes of certificates or perform frequent cryptographic operations. The vulnerability affects any system where Bouncy Castle is used for certificate validation, including web servers, application servers, and cryptographic service providers that rely on the library's EC certificate processing capabilities.
Mitigation strategies for CVE-2024-29857 primarily involve upgrading to Bouncy Castle version 1.78 or later, which includes proper parameter validation and optimization measures to prevent excessive CPU consumption. Organizations should conduct comprehensive vulnerability assessments to identify all systems using affected Bouncy Castle versions and prioritize remediation efforts accordingly. Additional defensive measures include implementing certificate validation timeouts, monitoring for unusual CPU consumption patterns during certificate processing, and establishing robust patch management procedures to ensure timely deployment of security updates. This vulnerability aligns with CWE-775, which addresses improper handling of resources that can lead to denial of service conditions, and maps to ATT&CK technique T1499.004 for resource exhaustion attacks. Security teams should also consider implementing network segmentation and access controls to limit exposure and establish incident response procedures for detecting and responding to potential exploitation attempts.