vuln-cve/data/2026/5xxx/CVE-2026-5477.json

{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-5477",
        "assignerOrgId": "50d2cd11-d01a-48ed-9441-5bfce9d63b27",
        "state": "PUBLISHED",
        "assignerShortName": "wolfSSL",
        "dateReserved": "2026-04-03T07:59:59.388Z",
        "datePublished": "2026-04-10T05:06:22.884Z",
        "dateUpdated": "2026-04-10T14:04:00.411Z"
    },
    "containers": {
        "cna": {
            "providerMetadata": {
                "orgId": "50d2cd11-d01a-48ed-9441-5bfce9d63b27",
                "shortName": "wolfSSL",
                "dateUpdated": "2026-04-10T05:06:22.884Z"
            },
            "title": "Prefix-substitution forgery via integer overflow in wolfCrypt CMAC",
            "problemTypes": [
                {
                    "descriptions": [
                        {
                            "lang": "en",
                            "cweId": "CWE-190",
                            "description": "CWE-190 Integer overflow or wraparound",
                            "type": "CWE"
                        }
                    ]
                }
            ],
            "affected": [
                {
                    "vendor": "wolfSSL",
                    "product": "wolfSSL",
                    "modules": [
                        "wc_CmacUpdate"
                    ],
                    "programFiles": [
                        "wolfcrypt/src/cmac.c",
                        "wolfcrypt/src/aes.c"
                    ],
                    "versions": [
                        {
                            "status": "affected",
                            "version": "0",
                            "lessThanOrEqual": "5.9.0",
                            "versionType": "semver"
                        }
                    ],
                    "defaultStatus": "unaffected"
                }
            ],
            "descriptions": [
                {
                    "lang": "en",
                    "value": "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.",
                    "supportingMedia": [
                        {
                            "type": "text/html",
                            "base64": false,
                            "value": "An integer overflow existed in the wolfCrypt CMAC implementation, that could be exploited to forge CMAC tags. The function wc_CmacUpdate used the&nbsp;<span>guard `if (cmac-&gt;totalSz != 0)` to skip XOR-chaining on </span><span>the first block (where digest is all-zeros and the XOR is a no-op).&nbsp;</span><span>However, totalSz is word32 and wraps to zero after 2^28 block flushes </span><span>(4 GiB), causing the guard to erroneously discard the </span><span>live CBC-MAC chain state. Any two messages sharing a common suffix&nbsp;</span><span>beyond the 4 GiB mark then produce identical CMAC tags, enabling a </span><span>zero-work prefix-substitution forgery. The fix removes the guard,&nbsp;</span><span>making the XOR unconditional; the no-op property on the first block is </span><span>preserved because digest is zero-initialized by wc_InitCmac_ex.</span>"
                        }
                    ]
                }
            ],
            "references": [
                {
                    "url": "https://github.com/wolfSSL/wolfssl/pull/10102"
                }
            ],
            "metrics": [
                {
                    "format": "CVSS",
                    "scenarios": [
                        {
                            "lang": "en",
                            "value": "GENERAL"
                        }
                    ],
                    "cvssV4_0": {
                        "attackVector": "NETWORK",
                        "attackComplexity": "LOW",
                        "attackRequirements": "PRESENT",
                        "privilegesRequired": "NONE",
                        "userInteraction": "NONE",
                        "vulnConfidentialityImpact": "NONE",
                        "subConfidentialityImpact": "NONE",
                        "vulnIntegrityImpact": "HIGH",
                        "subIntegrityImpact": "NONE",
                        "vulnAvailabilityImpact": "NONE",
                        "subAvailabilityImpact": "NONE",
                        "exploitMaturity": "NOT_DEFINED",
                        "Safety": "NOT_DEFINED",
                        "Automatable": "NOT_DEFINED",
                        "Recovery": "NOT_DEFINED",
                        "valueDensity": "NOT_DEFINED",
                        "vulnerabilityResponseEffort": "NOT_DEFINED",
                        "providerUrgency": "NOT_DEFINED",
                        "version": "4.0",
                        "baseSeverity": "HIGH",
                        "baseScore": 8.2,
                        "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N"
                    }
                }
            ],
            "credits": [
                {
                    "lang": "en",
                    "value": "Calif.io in collaboration with Claude and Anthropic Research",
                    "type": "finder"
                }
            ],
            "source": {
                "discovery": "EXTERNAL"
            },
            "x_generator": {
                "engine": "Vulnogram 1.0.1"
            }
        },
        "adp": [
            {
                "metrics": [
                    {
                        "other": {
                            "type": "ssvc",
                            "content": {
                                "timestamp": "2026-04-10T14:03:53.265423Z",
                                "id": "CVE-2026-5477",
                                "options": [
                                    {
                                        "Exploitation": "none"
                                    },
                                    {
                                        "Automatable": "yes"
                                    },
                                    {
                                        "Technical Impact": "partial"
                                    }
                                ],
                                "role": "CISA Coordinator",
                                "version": "2.0.3"
                            }
                        }
                    }
                ],
                "title": "CISA ADP Vulnrichment",
                "providerMetadata": {
                    "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
                    "shortName": "CISA-ADP",
                    "dateUpdated": "2026-04-10T14:04:00.411Z"
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        ]
    }
}