{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-73261",
        "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "state": "PUBLISHED",
        "assignerShortName": "GitHub_M",
        "dateReserved": "2026-08-11T17:18:01.598Z",
        "datePublished": "2026-10-14T18:25:41.102Z",
        "dateUpdated": "2026-10-14T18:25:41.102Z"
    },
    "containers": {
        "cna": {
            "title": "Mongoose: handle_opt() missing opts[1] > len check — 1-byte OOB read corrupts TCP MSS, silences mg_send() per connection",
            "problemTypes": [
                {
                    "descriptions": [
                        {
                            "cweId": "CWE-20",
                            "lang": "en",
                            "description": "CWE-20: Improper Input Validation",
                            "type": "CWE"
                        }
                    ]
                },
                {
                    "descriptions": [
                        {
                            "cweId": "CWE-125",
                            "lang": "en",
                            "description": "CWE-125: Out-of-bounds Read",
                            "type": "CWE"
                        }
                    ]
                }
            ],
            "metrics": [
                {
                    "cvssV3_1": {
                        "attackComplexity": "LOW",
                        "attackVector": "NETWORK",
                        "availabilityImpact": "HIGH",
                        "baseScore": 7.5,
                        "baseSeverity": "HIGH",
                        "confidentialityImpact": "NONE",
                        "integrityImpact": "NONE",
                        "privilegesRequired": "NONE",
                        "scope": "UNCHANGED",
                        "userInteraction": "NONE",
                        "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
                        "version": "3.1"
                    }
                }
            ],
            "references": [
                {
                    "name": "https://github.com/cesanta/mongoose/security/advisories/GHSA-3fmr-92g4-wchx",
                    "tags": [
                        "x_refsource_CONFIRM"
                    ],
                    "url": "https://github.com/cesanta/mongoose/security/advisories/GHSA-3fmr-92g4-wchx"
                },
                {
                    "name": "https://github.com/cesanta/mongoose/commit/cc7c6d2d18c28fcc6d085633dddd88402946140a",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/cesanta/mongoose/commit/cc7c6d2d18c28fcc6d085633dddd88402946140a"
                },
                {
                    "name": "https://github.com/cesanta/mongoose/releases/tag/7.23",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/cesanta/mongoose/releases/tag/7.23"
                }
            ],
            "affected": [
                {
                    "vendor": "cesanta",
                    "product": "mongoose",
                    "versions": [
                        {
                            "version": "< 7.23",
                            "status": "affected"
                        }
                    ]
                }
            ],
            "providerMetadata": {
                "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
                "shortName": "GitHub_M",
                "dateUpdated": "2026-10-14T18:25:41.102Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "Mongoose is an embedded web server and network library. Prior to 7.23, the built-in TCP/IP stack enabled by MG_ENABLE_TCPIP in src/net_builtin.c does not reject a TCP option whose declared opts[1] length exceeds the remaining option bytes. In handle_opt(), a NOP followed by a truncated MSS option causes opts[3] to be read outside the declared options area and used as the low byte of dmss. An unauthenticated remote peer can corrupt the per-connection MSS value so later mg_send() calls transmit truncated or zero-length application payloads while the TCP connection otherwise appears healthy. This issue is fixed in version 7.23."
                }
            ],
            "source": {
                "advisory": "GHSA-3fmr-92g4-wchx",
                "discovery": "UNKNOWN"
            }
        }
    }
}