CVE-2019-17596 in Google
Summary
by MITRE
Go before 1.12.11 and 1.3.x before 1.13.2 can panic upon an attempt to process network traffic containing an invalid DSA public key. There are several attack scenarios, such as traffic from a client to a server that verifies client certificates.
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Analysis
by VulDB Data Team • 05/21/2025
The vulnerability identified as CVE-2019-17596 represents a critical security flaw in the go programming language implementation that affects versions prior to 1.12.11 and 1.13.2. This issue manifests as a panic condition when the go runtime attempts to process network traffic containing an invalid DSA public key, creating a potential denial of service scenario that can be exploited by remote attackers. The vulnerability specifically impacts applications that utilize TLS connections and certificate verification mechanisms, particularly those that validate client certificates in server-side applications. The flaw stems from inadequate input validation within the cryptographic processing routines that handle DSA (Digital Signature Algorithm) public keys during network communication.
The technical implementation of this vulnerability occurs within the go standard library's crypto package where the runtime fails to properly handle malformed DSA public keys during certificate processing. When a client attempts to establish a TLS connection with a server that requires client certificate authentication, and the client presents a certificate containing an invalid DSA public key, the go runtime crashes with a panic condition rather than gracefully handling the malformed input. This behavior violates the principle of graceful degradation and can be exploited by attackers to disrupt services through carefully crafted network traffic. The vulnerability is classified under CWE-248 as an "Uncaught Exception" and represents a failure to properly handle exceptional conditions in cryptographic operations. The panic condition occurs at the runtime level rather than being caught and handled by application code, making it particularly dangerous as it can bring down entire services.
The operational impact of CVE-2019-17596 extends beyond simple service disruption to encompass broader security implications for systems relying on go-based applications. Attackers can leverage this vulnerability to perform denial of service attacks against web servers, API endpoints, and other network services that utilize go's TLS implementation with client certificate validation enabled. The attack scenario becomes particularly concerning in environments where client certificates are mandatory for authentication, such as enterprise applications, internal APIs, or services requiring mutual TLS authentication. The vulnerability affects any go application that processes TLS connections with client certificate verification, including but not limited to web servers, proxy services, and microservices architectures. Organizations running go applications in production environments are at risk of service interruption, increased operational overhead, and potential business impact when this vulnerability is exploited.
Mitigation strategies for CVE-2019-17596 primarily focus on upgrading affected go installations to versions 1.12.11 or 1.13.2, which contain the necessary patches to properly handle invalid DSA public keys. System administrators should conduct thorough vulnerability assessments to identify all go-based applications and services that may be exposed to this risk, particularly those utilizing TLS client certificate validation. Organizations should implement network monitoring solutions to detect potential exploitation attempts and establish incident response procedures for handling service disruptions. Additionally, developers should review their application code to ensure proper error handling around cryptographic operations and implement defensive programming practices. The vulnerability also highlights the importance of following security best practices such as regularly updating dependencies, implementing proper input validation, and conducting security testing of cryptographic implementations. Organizations should consider implementing network segmentation and access controls to limit exposure and reduce the potential impact of exploitation attempts. Compliance with security standards such as those outlined in the NIST SP 800-53 and ISO/IEC 27001 frameworks becomes critical when managing applications vulnerable to such runtime exceptions in cryptographic libraries.