{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-33021",
        "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "state": "PUBLISHED",
        "assignerShortName": "GitHub_M",
        "dateReserved": "2026-03-17T17:22:14.667Z",
        "datePublished": "2026-04-14T21:57:22.817Z",
        "dateUpdated": "2026-04-16T13:54:36.177Z"
    },
    "containers": {
        "cna": {
            "title": "libsixel: Use-after-free in sixel_encoder_encode_bytes()",
            "problemTypes": [
                {
                    "descriptions": [
                        {
                            "cweId": "CWE-416",
                            "lang": "en",
                            "description": "CWE-416: Use After Free",
                            "type": "CWE"
                        }
                    ]
                }
            ],
            "metrics": [
                {
                    "cvssV3_1": {
                        "attackComplexity": "LOW",
                        "attackVector": "LOCAL",
                        "availabilityImpact": "HIGH",
                        "baseScore": 7.3,
                        "baseSeverity": "HIGH",
                        "confidentialityImpact": "LOW",
                        "integrityImpact": "LOW",
                        "privilegesRequired": "NONE",
                        "scope": "UNCHANGED",
                        "userInteraction": "NONE",
                        "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:H",
                        "version": "3.1"
                    }
                }
            ],
            "references": [
                {
                    "name": "https://github.com/saitoha/libsixel/security/advisories/GHSA-j6m5-2cc7-3whc",
                    "tags": [
                        "x_refsource_CONFIRM"
                    ],
                    "url": "https://github.com/saitoha/libsixel/security/advisories/GHSA-j6m5-2cc7-3whc"
                },
                {
                    "name": "https://github.com/saitoha/libsixel/releases/tag/v1.8.7-r1",
                    "tags": [
                        "x_refsource_MISC"
                    ],
                    "url": "https://github.com/saitoha/libsixel/releases/tag/v1.8.7-r1"
                }
            ],
            "affected": [
                {
                    "vendor": "saitoha",
                    "product": "libsixel",
                    "versions": [
                        {
                            "version": "< 1.8.7-r1",
                            "status": "affected"
                        }
                    ]
                }
            ],
            "providerMetadata": {
                "orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
                "shortName": "GitHub_M",
                "dateUpdated": "2026-04-14T21:57:22.817Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "libsixel is a SIXEL encoder/decoder implementation derived from kmiya's sixel. Versions 1.8.7 and prior contain a use-after-free vulnerability in sixel_encoder_encode_bytes() because sixel_frame_init() stores the caller-owned pixel buffer pointer directly in frame->pixels without making a defensive copy. When a resize operation is triggered, sixel_frame_convert_to_rgb888() unconditionally frees this caller-owned buffer and replaces it with a new internal allocation, leaving the caller with a dangling pointer. Any subsequent access to the original buffer by the caller constitutes a use-after-free, confirmed by AddressSanitizer. An attacker who controls incoming frames can trigger this bug repeatedly and predictably, resulting in a reliable crash with potential for code execution. This issue has been fixed in version 1.8.7-r1."
                }
            ],
            "source": {
                "advisory": "GHSA-j6m5-2cc7-3whc",
                "discovery": "UNKNOWN"
            }
        },
        "adp": [
            {
                "metrics": [
                    {
                        "other": {
                            "type": "ssvc",
                            "content": {
                                "timestamp": "2026-04-16T13:54:16.495174Z",
                                "id": "CVE-2026-33021",
                                "options": [
                                    {
                                        "Exploitation": "poc"
                                    },
                                    {
                                        "Automatable": "no"
                                    },
                                    {
                                        "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": "2026-04-16T13:54:36.177Z"
                }
            }
        ]
    }
}