CVE-2026-5477 Detail
Received
This CVE record has recently been published to the CVE List and has been included within the NVD dataset. DescriptionAn 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. Metrics
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Weakness Enumeration
Quick InfoCVE Dictionary Entry:CVE-2026-5477 NVD Published Date: 04/10/2026 NVD Last Modified: 04/10/2026 Source: wolfSSL Inc. |
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