CVE-2026-10832 in WildFly
Summary
by MITRE • 09/18/2026
A flaw was found in the DERDecoder class within wildfly-elytron-asn1. A remote attacker can exploit this resource exhaustion vulnerability by sending a specially crafted DER (Distinguished Encoding Rules) payload. The decoder attempts to allocate excessive memory based on an inflated length value without proper validation, leading to Java Virtual Machine (JVM) memory exhaustion. This results in a remote Denial of Service (DoS) for services that process untrusted DER/ASN.1 input, including SASL (Simple Authentication and Security Layer) authentication mechanisms and X.500 certificate principal parsing paths.
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Analysis
by VulDB Data Team • 09/18/2026
The vulnerability identified within the wildfly-elytron-asn1 component represents a critical resource exhaustion flaw located in the DERDecoder class. This security issue stems from an improper validation of input data during the decoding process for Distinguished Encoding Rules, which are commonly used to encode ASN.1 structures such as X.509 certificates and cryptographic keys. The core technical failure lies in the decoder's inability to properly verify length fields before initiating memory allocation operations. When a remote attacker submits a specially crafted DER payload containing an inflated or maliciously manipulated length value, the application attempts to allocate a corresponding amount of heap memory based on this untrusted input. Because there is no upper bound check or sanity validation applied to these length parameters prior to allocation, the Java Virtual Machine can be forced to consume excessive amounts of available memory in a short period.
This mechanism directly leads to a remote Denial of Service condition for any service that processes untrusted DER or ASN.1 input streams. The impact is particularly severe because wildfly-elytron-asn1 serves as a foundational library for several critical authentication and security protocols within the WildFly application server ecosystem. Specifically, this vulnerability affects SASL mechanisms which rely on binary data encoding for challenge-response exchanges, as well as X.500 certificate principal parsing paths used during mutual TLS or client certificate authentication scenarios. An attacker who can interact with these endpoints remotely does not need to authenticate successfully; they merely need to send the malformed payload to trigger the memory exhaustion event. This effectively renders the targeted service unavailable by causing the JVM process to crash due to OutOfMemoryError conditions, thereby disrupting business continuity and potentially masking other malicious activities through system instability.
From a classification perspective, this vulnerability aligns with CWE-400, which describes uncontrolled resource consumption, specifically manifesting as memory exhaustion. The attack vector is categorized under ATT&CK technique T1496, representing Resource Hijacking where an attacker consumes resources to degrade service availability rather than compromising data integrity or confidentiality directly. While the primary impact is denial of service, such instability can sometimes be leveraged in conjunction with other attacks to cause race conditions or bypass certain security checks during system restarts or error recovery phases.
Mitigation strategies must focus on implementing strict input validation and length constraints within the DER decoding logic. Developers should enforce maximum allowable limits for ASN.1 element lengths before attempting any memory allocation, ensuring that the requested size does not exceed predefined thresholds based on expected protocol specifications. Additionally, applying rate limiting to endpoints that accept raw binary DER inputs can help mitigate the impact of automated exploitation attempts. For organizations using WildFly or related JBoss products, it is imperative to apply vendor-provided patches as soon as they become available. In environments where immediate patching is not feasible, deploying a Web Application Firewall with rules capable of detecting anomalous ASN.1 structures or excessively large binary payloads can provide an additional layer of defense against this specific exploitation vector until the underlying code issue is resolved.