Bug 2545493 (CVE-2026-71883)

Summary: CVE-2026-71883 org.bouncycastle/bcprov-lts8on: Bouncy Castle for Java LTS: Information disclosure via improper memory handling during in-place encryption
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: ewittman, janstey, nipatil, pantinor, rkubis
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in Bouncy Castle for Java LTS. This flaw can lead to information disclosure when an application performs in-place encryption using native packet ciphers. Due to improper memory handling in native code bindings, the library overwrites the newly produced ciphertext with the original unencrypted key or input data. As a result, an attacker could obtain the raw secret key because the application unknowingly stores or transmits the unencrypted key in place of the intended ciphertext.
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Description OSIDB Bzimport 2026-10-03 08:51:16 UTC 
In Bouncy Castle for Java LTS before 2.73.13, the one-shot native packet ciphers for AES-CBC, CCM, CFB, CTR, GCM and GCM-SIV released the caller's key, IV and additional authenticated data arrays with JNI's ReleaseByteArrayElements in mode 0, which commits the native copy back into the Java array. Those arrays are read-only to the native code, and on a JVM that returns a copy rather than a pin the copy still holds the input bytes as they were read. The output buffer is taken through a separate critical region and committed first, so where an application passed the same Java array as both an input and the destination - encrypting in place over KeyParameter.getKey(), for example - the later mode-0 release of the key wrote the unchanged key bytes over the ciphertext that had just been produced. The call still returned the correct output length, so an application encrypting in place over its own key array was handed the raw AES key where it expected ciphertext, with nothing in the API to indicate it, and would transmit or store the key in place of the message. The read-only input arrays are now released with JNI_ABORT, freeing the native copy without copying it back, and mode 0 is reserved for arrays the native code wrote. The pure-Java packet ciphers and the streaming native modes are not affected. Bouncy Castle for Java (bcprov) is not affected, as it ships no native implementations.