CVE-2026-8798
Received Received - Intake

Denial of Service in Bouncy Castle FIPS Java

Publication date: 2026-08-08

Last updated on: 2026-08-08

Assigner: bcorg

Description
In Bouncy Castle for Java FIPS (BC-FJA) before bc-fips 2.1.3, the native entropy source used on Intel platforms retried the CPU entropy instructions without any bound. RDSEED and RDRAND report failure through their carry flag, and the JNI seeding routine spun re-issuing the instruction for as long as that flag stayed clear, so a persistent failure of the on-chip entropy source - whether from a hardware fault, from the underlying DRBG being exhausted by contention across many cores, or from a hypervisor that does not provide the instruction - left the calling thread looping indefinitely inside the JNI call, where it could be neither interrupted nor timed out. Any operation drawing from the native entropy source could therefore hang, denying service to the application. The retry loops are now bounded (200 attempts for RDSEED and 20 for RDRAND, twice the baselines given in Intel's Digital Random Number Generator software implementation guide), pausing between attempts and, on exhaustion, clearing any partially written buffer and throwing rather than continuing to spin. The clear is performed by an un-elidable memzero, which uses a volatile pointer and an assembly memory barrier so that a compiler cannot optimise the erase away as a dead store. Bouncy Castle for Java (bcprov) is not affected, as it has no native entropy source; the 1.0.X and 2.0.X FIPS series are not affected.

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Meta Information

Published
2026-08-08
Last Modified
2026-08-08
Generated
2026-08-08
AI Q&A
2026-08-08
EPSS Evaluated
N/A
NVD
CVE-2026-8798
EUVD
EUVD-2026-54725

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
bouncy_castle bc-fja to 2.1.3 (exc)

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Exploitability

CWE
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KEV
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CWE ID Description
CWE-835 The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop.

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Executive Summary

CVE-2026-8798 is a denial-of-service vulnerability in Bouncy Castle's FIPS Java library (BC-FJA) before version 2.1.3. It affects Intel platforms using native entropy sources (RDSEED and RDRAND instructions). The issue occurs when entropy collection fails, causing the library to retry indefinitely without bounds. This freezes any thread relying on the entropy source, as the infinite loop cannot be interrupted from Java code.

Detection Guidance

Check if your system uses Bouncy Castle FIPS Java library (BC-FJA) version before 2.1.3 on Intel platforms. Inspect the library version in your Java environment or application dependencies. Look for hanging threads or processes during entropy collection operations, which may indicate the vulnerability.

Impact Analysis

This vulnerability can cause applications to hang or crash if they depend on the native entropy source for cryptographic operations. Services using BC-FJA on Intel platforms may become unresponsive, leading to denial of service. The impact is limited to systems using affected BC-FJA versions with native entropy enabled.

Compliance Impact

This vulnerability could impact compliance with standards like GDPR and HIPAA by causing denial-of-service conditions. If entropy collection fails, operations relying on the native entropy source may hang indefinitely, disrupting critical functions such as encryption or authentication. This could lead to unauthorized access or data processing delays, violating availability requirements in GDPR and HIPAA.

Mitigation Strategies

Upgrade Bouncy Castle FIPS Java library (BC-FJA) to version 2.1.3 or later. Disable native entropy support if not required. Monitor system logs for hanging threads or processes related to entropy collection.

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