CVE-2026-95616
Received Received - Intake

Integer Overflow in Apache WSS4J Leading to DoS

Publication date: 2026-09-30

Last updated on: 2026-09-30

Assigner: Apache Software Foundation

Description
An integer overflow in WSS4J's DER bounds check lets an oversized allocation pass validation. An unauthenticated attacker can send a SOAP message carrying an X.509 certificate whose SubjectKeyIdentifier extension declares a length of 0x7FFFFFFF; WSS4J decodes this while resolving the signature's key reference, before the message is authenticated, so an eleven-byte extension triggers a 2 GB allocation. Repeated requests exhaust server memory. Users are recommended to upgrade to versions 4.0.2 or 3.0.6 or 2.4.4, which fix this issue.

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Meta Information

Published
2026-09-30
Last Modified
2026-09-30
Generated
2026-09-30
AI Q&A
2026-09-30
EPSS Evaluated
N/A
NVD
CVE-2026-95616
EUVD
EUVD-2026-89801

Affected Vendors & Products

Showing 3 associated CPEs
Vendor Product Version / Range
apache wss4j 4.0.2
apache wss4j 3.0.6
apache wss4j 2.4.4

Helpful Resources

Exploitability

CWE
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KEV
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CWE ID Description
CWE-190 The product performs a calculation that can produce an integer overflow or wraparound when the logic assumes that the resulting value will always be larger than the original value. This occurs when an integer value is incremented to a value that is too large to store in the associated representation. When this occurs, the value may become a very small or negative number.

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Executive Summary

CVE-2026-95616 is an integer overflow vulnerability in Apache WSS4J's DER bounds check during X.509 certificate processing. An attacker sends a SOAP message with a crafted certificate containing a SubjectKeyIdentifier extension declaring a length of 0x7FFFFFFF. This causes WSS4J to attempt a 2 GB memory allocation while resolving the signature's key reference, even before authenticating the message. Repeated requests can exhaust server memory, leading to denial of service.

Detection Guidance

Detecting this vulnerability requires monitoring for unusual memory allocation patterns or crashes in Apache WSS4J services processing SOAP messages with X.509 certificates. Check logs for repeated memory exhaustion errors or OOM (Out of Memory) events during certificate parsing. Use tools like netstat or ss to monitor network connections for suspicious SOAP traffic patterns.

Impact Analysis

This vulnerability allows unauthenticated attackers to crash or severely degrade the performance of servers running vulnerable versions of Apache WSS4J by sending specially crafted SOAP messages. This can result in denial of service, making services unavailable to legitimate users.

Mitigation Strategies

Immediately upgrade Apache WSS4J to version 2.4.4, 3.0.6, or 4.0.2 or later. If upgrading is not possible, restrict access to SOAP endpoints via network firewalls or WAF rules to block malformed certificate requests. Monitor system memory usage for signs of exploitation attempts.

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