CVE-2026-5477
Gravedad CVSS v4.0:
ALTA
Tipo:
CWE-190
Desbordamiento o ajuste de enteros
Fecha de publicación:
10/04/2026
Última modificación:
10/04/2026
Descripción
*** Pendiente de traducción *** An integer overflow existed in the wolfCrypt CMAC implementation, that could be exploited to forge CMAC tags. The function wc_CmacUpdate used the guard `if (cmac->totalSz != 0)` to skip XOR-chaining on the first block (where digest is all-zeros and the XOR is a no-op). However, totalSz is word32 and wraps to zero after 2^28 block flushes (4 GiB), causing the guard to erroneously discard the live CBC-MAC chain state. Any two messages sharing a common suffix beyond the 4 GiB mark then produce identical CMAC tags, enabling a zero-work prefix-substitution forgery. The fix removes the guard, making the XOR unconditional; the no-op property on the first block is preserved because digest is zero-initialized by wc_InitCmac_ex.
Impacto
Puntuación base 4.0
8.20
Gravedad 4.0
ALTA