Legion of the Bouncy Castle Bouncy Castle for Java FIPS up to 2.1.2 Native Entropy Source infinite loop

Summaryinfo

A vulnerability categorized as problematic has been discovered in Legion of the Bouncy Castle Bouncy Castle for Java FIPS up to 2.1.2. This affects an unknown part of the component Native Entropy Source. Executing a manipulation can lead to infinite loop. This vulnerability is handled as CVE-2026-8798. The attack can be executed remotely. There is not any exploit available.

Detailsinfo

A vulnerability classified as problematic was found in Legion of the Bouncy Castle Bouncy Castle for Java FIPS up to 2.1.2. This vulnerability affects an unknown functionality of the component Native Entropy Source. The manipulation with an unknown input leads to a infinite loop vulnerability. The CWE definition for the vulnerability is CWE-835. The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop. As an impact it is known to affect availability. CVE summarizes:

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.

The advisory is shared for download at github.com. This vulnerability was named CVE-2026-8798 since 05/18/2026. The exploitation appears to be easy. The attack can be initiated remotely. No form of authentication is required for a successful exploitation. There are neither technical details nor an exploit publicly available. The MITRE ATT&CK project declares the attack technique as T1499.

Upgrading to version 2.1.3 eliminates this vulnerability.

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Productinfo

Type

• Programming Language Software

Vendor

• Legion of the Bouncy Castle

Name

• Bouncy Castle for Java FIPS

Version

• 2.1.0
• 2.1.1
• 2.1.2

CPE 2.3info

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CPE 2.2info

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