{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-112021",
        "assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
        "state": "PUBLISHED",
        "assignerShortName": "VulnCheck",
        "dateReserved": "2026-10-18T01:24:56.329Z",
        "datePublished": "2026-10-18T11:38:40.652Z",
        "dateUpdated": "2026-10-18T11:38:40.652Z"
    },
    "containers": {
        "cna": {
            "providerMetadata": {
                "orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
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                "dateUpdated": "2026-10-18T11:38:40.652Z"
            },
            "datePublic": "2026-07-08T00:00:00.000Z",
            "title": "snac2 before 2.93 Heap-Based Buffer Overflow via JSON Parser _xs_json_load_lexer()",
            "descriptions": [
                {
                    "lang": "en",
                    "value": "snac2 before 2.93 contains a heap-based buffer overflow vulnerability in _xs_json_load_lexer() that allows unauthenticated remote attackers to corrupt heap memory by sending JSON strings containing a \\u0000 escape. Attackers can send a single crafted application/activity+json POST to activitypub_post_handler(), which parses it before signature checks, overflowing heap allocations and crashing the server."
                }
            ],
            "problemTypes": [
                {
                    "descriptions": [
                        {
                            "lang": "en",
                            "description": "Heap-based Buffer Overflow",
                            "cweId": "CWE-122",
                            "type": "CWE"
                        }
                    ]
                }
            ],
            "affected": [
                {
                    "vendor": "grunfink",
                    "product": "snac2",
                    "defaultStatus": "unaffected",
                    "versions": [
                        {
                            "version": "0",
                            "lessThan": "2.93",
                            "status": "affected",
                            "versionType": "custom"
                        }
                    ],
                    "repo": "https://codeberg.org/grunfink/snac2"
                }
            ],
            "metrics": [
                {
                    "format": "CVSS",
                    "cvssV4_0": {
                        "version": "4.0",
                        "vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
                        "attackVector": "NETWORK",
                        "attackComplexity": "LOW",
                        "attackRequirements": "NONE",
                        "privilegesRequired": "NONE",
                        "userInteraction": "NONE",
                        "vulnConfidentialityImpact": "NONE",
                        "vulnIntegrityImpact": "NONE",
                        "vulnAvailabilityImpact": "HIGH",
                        "subConfidentialityImpact": "NONE",
                        "subIntegrityImpact": "NONE",
                        "subAvailabilityImpact": "NONE",
                        "baseScore": 8.7,
                        "baseSeverity": "HIGH"
                    }
                },
                {
                    "format": "CVSS",
                    "cvssV3_1": {
                        "version": "3.1",
                        "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
                        "attackVector": "NETWORK",
                        "attackComplexity": "LOW",
                        "privilegesRequired": "NONE",
                        "userInteraction": "NONE",
                        "scope": "UNCHANGED",
                        "confidentialityImpact": "NONE",
                        "integrityImpact": "NONE",
                        "availabilityImpact": "HIGH",
                        "baseScore": 7.5,
                        "baseSeverity": "HIGH"
                    }
                }
            ],
            "references": [
                {
                    "url": "https://nullenvk.pl/posts/02-snac2-json",
                    "tags": [
                        "technical-description"
                    ]
                },
                {
                    "url": "https://gist.github.com/nullenvk/2bf288e2d34cb3d4b7143e61dbf7d90b",
                    "tags": [
                        "exploit"
                    ]
                },
                {
                    "url": "https://codeberg.org/grunfink/snac2/src/tag/2.92/xs_json.h#L283-L285",
                    "tags": [
                        "technical-description"
                    ]
                },
                {
                    "url": "https://codeberg.org/grunfink/snac2/commit/ec2c5c2046e0381bc942ec5d0d05ec861fe377e7",
                    "tags": [
                        "patch"
                    ]
                },
                {
                    "url": "https://codeberg.org/grunfink/snac2/releases/tag/2.93",
                    "tags": [
                        "release-notes"
                    ]
                },
                {
                    "url": "https://codeberg.org/grunfink/snac2",
                    "tags": [
                        "product"
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                },
                {
                    "name": "VulnCheck Advisory: snac2 before 2.93 Heap-Based Buffer Overflow via JSON Parser _xs_json_load_lexer()",
                    "tags": [
                        "third-party-advisory"
                    ],
                    "url": "https://www.vulncheck.com/advisories/snac2-before-2.93-heap-based-buffer-overflow-via-json-parser-xs-json-load-lexer"
                }
            ],
            "credits": [
                {
                    "lang": "en",
                    "value": "nullenvk",
                    "type": "finder"
                }
            ],
            "x_generator": {
                "engine": "vulncheck-endgame"
            }
        }
    }
}