CVE-2026-10832 Overview
A resource exhaustion vulnerability exists in the DERDecoder class of the wildfly-elytron-asn1 library. A remote attacker can trigger Java Virtual Machine (JVM) memory exhaustion by sending a specially crafted Distinguished Encoding Rules (DER) payload. The decoder allocates memory based on an inflated length field without validating it against the actual input size. Services that parse untrusted DER or ASN.1 input are exposed, including Simple Authentication and Security Layer (SASL) authentication mechanisms and X.500 certificate principal parsing paths. Successful exploitation results in a remote Denial of Service (DoS) condition against affected WildFly Elytron deployments. The flaw is tracked under CWE-770: Allocation of Resources Without Limits or Throttling.
Critical Impact
Remote unauthenticated attackers can exhaust JVM memory and disrupt authentication and certificate parsing services processing untrusted DER/ASN.1 input.
Affected Products
- wildfly-elytron-asn1 library (DERDecoder component)
- Red Hat products shipping wildfly-elytron (see RHSA-2026:70228, RHSA-2026:70229, RHSA-2026:70230)
- Additional Red Hat components addressed in RHSA-2026:70277
Discovery Timeline
- 2026-09-18 - CVE-2026-10832 published to NVD
- 2026-09-22 - Last updated in NVD database
Technical Details for CVE-2026-10832
Vulnerability Analysis
The DERDecoder class parses ASN.1 structures encoded with Distinguished Encoding Rules. DER-encoded objects declare their content length in a length prefix that follows the type tag. The vulnerable decoder reads this length field and allocates a buffer sized accordingly before validating that the payload actually contains that many bytes. An attacker who sends a small DER payload declaring a very large length forces the JVM to attempt an allocation proportional to the attacker-controlled value. Repeated or single large requests exhaust heap memory and cause OutOfMemoryError conditions in the target process.
Affected code paths include SASL authentication handling and X.500 principal name parsing during certificate processing. These paths accept untrusted input from network peers before authentication completes, exposing the vulnerability to unauthenticated remote attackers.
Root Cause
The root cause is missing input validation between the declared length field in the DER header and the actual byte length of the received payload. The decoder trusts the attacker-supplied length when sizing internal buffers, which maps to [CWE-770: Allocation of Resources Without Limits or Throttling].
Attack Vector
The attack is delivered over the network with no authentication or user interaction required. An attacker sends a crafted DER/ASN.1 blob to any listener that feeds input into DERDecoder, such as a SASL authentication endpoint or a TLS listener that parses client certificate principals. The elevated attack complexity reflects the need to reach a code path that actually invokes the vulnerable decoder on attacker-controlled bytes.
No public proof-of-concept exploit code was available at the time of publication. Refer to the Red Hat CVE Report and Red Hat Bug #2484703 for vendor technical detail.
Detection Methods for CVE-2026-10832
Indicators of Compromise
- JVM java.lang.OutOfMemoryError: Java heap space entries in WildFly or application server logs correlated with SASL or TLS handshake activity.
- Sudden garbage collection storms or heap growth on hosts running wildfly-elytron immediately after receiving external connections.
- Repeated connection attempts from a single source that terminate abnormally during authentication or certificate parsing.
Detection Strategies
- Ingest application server logs and JVM garbage collection metrics into a centralized analytics platform and alert on OutOfMemoryError events tied to Elytron classes.
- Monitor network telemetry for anomalous DER/ASN.1 payloads targeting SASL or LDAPS listeners, particularly small requests with oversized length fields.
- Correlate JVM memory pressure alerts with source IP concentration to identify targeted DoS attempts.
Monitoring Recommendations
- Enable heap dump on OutOfMemoryError and route dumps to forensic storage for post-incident analysis.
- Track process availability and restart counts for services fronted by wildfly-elytron to detect DoS-induced crashes.
- Baseline normal DER/ASN.1 message sizes on authentication endpoints and alert on outliers.
How to Mitigate CVE-2026-10832
Immediate Actions Required
- Apply the vendor-provided updates referenced in RHSA-2026:70228, RHSA-2026:70229, RHSA-2026:70230, and RHSA-2026:70277 to affected WildFly and Red Hat middleware deployments.
- Restrict network exposure of SASL and certificate-based authentication endpoints to trusted networks until patching is complete.
- Configure JVM heap limits and restart policies so that memory exhaustion events fail fast and recover automatically.
Patch Information
Red Hat has released fixed packages via advisories RHSA-2026:70228, RHSA-2026:70229, RHSA-2026:70230, and RHSA-2026:70277. Consult the Red Hat CVE Report for CVE-2026-10832 for the authoritative list of fixed component versions.
Workarounds
- Place a network-level filter or reverse proxy in front of exposed listeners to enforce maximum request sizes on DER/ASN.1 payloads.
- Disable SASL mechanisms that rely on ASN.1 parsing if they are not required for business operations.
- Reduce the maximum JVM heap size so that a single malicious allocation attempt fails quickly without destabilizing the host.
# Example: restrict inbound payload size at a reverse proxy (nginx)
# and constrain JVM heap to fail fast on abusive allocations
client_max_body_size 64k;
# JVM startup flags for the WildFly process
-Xmx1g -XX:+HeapDumpOnOutOfMemoryError -XX:HeapDumpPath=/var/log/wildfly/heapdumps
Disclaimer: This content was generated using AI. While we strive for accuracy, please verify critical information with official sources.
