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CVE-2026-5477

Estado: AnalizadaAlta (8.2)—

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.

CVSS

Probabilidad de explotación (EPSS)

EPSS (Exploit Prediction Scoring System, de FIRST) estima la probabilidad de que una vulnerabilidad sea explotada en 30 días. Complementa a CVSS (impacto) y a CISA KEV (explotación confirmada).

🎯 Técnicas ATT&CK

Cómo se explota esta vulnerabilidad y qué consigue el atacante, en el lenguaje de MITRE ATT&CK.

Sobreflujo de enteros en wolfSSL CMAC remoto (AV:N, PR:N) permite falsificar tags; impacta integridad de autenticación (CWE-190) y puede manipular datos o sesiones autenticadas.

Inferido por nuestro agente de análisis a partir de la descripción oficial, el vector CVSS y la CWE, y comprobado por un supervisor. Puede contener errores.

🛡️ Mitigaciones ATT&CK que cubren estas técnicas

Vulnerability ScanningUser Account ManagementPrivileged Account ManagementNetwork SegmentationMulti-factor AuthenticationLimit Access to Resource Over Network

Tecnologías afectadas (1)

Wolfssl — Wolfssl

CWE

Referencias

JSON original (NVD)

Mostrar
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    }
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  "lastModified": "2026-06-17T10:59:06.143",
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