Concurrency Vulnerability in Zephyr's AES-GCM and ChaCha20-Poly1305 Implementations

CVE-2026-15890

What is CVE-2026-15890?

A concurrency vulnerability exists within the PSA Internal Trusted Storage transform module of Zephyr RTOS, specifically related to nonce management in AES-GCM and ChaCha20-Poly1305 encryption routines. The function responsible for nonce generation lacks proper synchronization, enabling simultaneous threads to increment a shared static nonce counter. This race condition can lead to the same nonce being reused across distinct encryption operations, which poses serious security risks, including the exposure of stored sensitive data and potential forgery of entries. The issue emphasizes the importance of serialization and mutex protection to prevent nonce overlap, particularly in environments where multiple threads may access the same UID concurrently.

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