CVE-2026-5477 Prefix-substitution forgery via integer overflow in wolfCrypt CMAC

An integer overflow existed in the wolfCrypt CMAC implementation, that could be exploited to forge CMAC tags. The function wcCmacUpdate 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 wrap...

CVE-2026-5477

An integer overflow existed in the wolfCrypt CMAC implementation, that could be exploited to forge CMAC tags. The function wcCmacUpdate 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 wrap...

CVE-2026-5477 Prefix-substitution forgery via integer overflow in wolfCrypt CMAC

An integer overflow existed in the wolfCrypt CMAC implementation, that could be exploited to forge CMAC tags. The function wcCmacUpdate 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 wrap...

CVE-2026-5477

The CVE-2026-5477 issue concerns wolfCrypt CMAC: an integer overflow in wc_CmacUpdate caused by a guard that skips XOR-chaining on the first block when cmac->totalSz != 0. totalSz is a 32-bit value and wraps to zero after 2^28 blocks (4 GiB), which can discard the live CBC-MAC chain state. Thi...

PT-2026-31875

Name of the Vulnerable Software and Affected Versions wolfCrypt affected versions not specified Description An integer overflow in the wolfCrypt CMAC implementation could allow for the forging of CMAC tags. The wc CmacUpdate function incorrectly skipped XOR-chaining on the first block due to a...

ANT-2026-ZZY4987K · wolfSSL · integer-overflow

integer-overflow high CVE-2026-5477 Severity Claude high · Security research firm high · Maintainer - Discovered by Claude Mythos Preview SECURITY RESEARCH FIRM ANALYSIS Triage and disclosure were performed by Calif. Verdict: true positive Severity: high TIMELINE Dates from discovery through publ...