{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2026-33020",
        "assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
        "state": "PUBLISHED",
        "assignerShortName": "GitHub_M",
        "dateReserved": "2026-03-17T17:22:14.667Z",
        "datePublished": "2026-04-14T21:53:00.388Z",
        "dateUpdated": "2026-04-15T13:30:47.463Z"
    },
    "containers": {
        "cna": {
            "title": "libsixel: Integer Overflow in write_png_to_file() leads to Heap-based Buffer Overflow",
            "problemTypes": [
                {
                    "descriptions": [
                        {
                            "cweId": "CWE-122",
                            "lang": "en",
                            "description": "CWE-122: Heap-based Buffer Overflow",
                            "type": "CWE"
                        }
                    ]
                },
                {
                    "descriptions": [
                        {
                            "cweId": "CWE-190",
                            "lang": "en",
                            "description": "CWE-190: Integer Overflow or Wraparound",
                            "type": "CWE"
                        }
                    ]
                }
            ],
            "metrics": [
                {
                    "cvssV3_1": {
                        "attackComplexity": "LOW",
                        "attackVector": "LOCAL",
                        "availabilityImpact": "HIGH",
                        "baseScore": 7.1,
                        "baseSeverity": "HIGH",
                        "confidentialityImpact": "NONE",
                        "integrityImpact": "HIGH",
                        "privilegesRequired": "NONE",
                        "scope": "UNCHANGED",
                        "userInteraction": "REQUIRED",
                        "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H",
                        "version": "3.1"
                    }
                }
            ],
            "references": [
                {
                    "name": "https://github.com/saitoha/libsixel/security/advisories/GHSA-2xgm-4x47-2x2p",
                    "tags": [
                        "x_refsource_CONFIRM"
                    ],
                    "url": "https://github.com/saitoha/libsixel/security/advisories/GHSA-2xgm-4x47-2x2p"
                },
                {
                    "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": "2026-04-14T21:53:00.388Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "libsixel is a SIXEL encoder/decoder implementation derived from kmiya's sixel. Versions 1.8.7 and prior contain an integer overflow which leads to a heap buffer overflow via sixel_frame_convert_to_rgb888() in frame.c, where allocation size and pointer offset computations for palettised images (PAL1, PAL2, PAL4) are performed using int arithmetic before casting to size_t. For images whose pixel count exceeds INT_MAX / 4, the overflow produces an undersized heap allocation for the conversion buffer and a negative pointer offset for the normalization sub-buffer, after which sixel_helper_normalize_pixelformat() writes the full image data starting from the invalid pointer, causing massive heap corruption confirmed by ASAN. An attacker providing a specially crafted large palettised PNG can corrupt the heap of the victim process, resulting in a reliable crash and potential arbitrary code execution.\nThis issue has been fixed in version 1.8.7-r1."
                }
            ],
            "source": {
                "advisory": "GHSA-2xgm-4x47-2x2p",
                "discovery": "UNKNOWN"
            }
        },
        "adp": [
            {
                "references": [
                    {
                        "url": "https://github.com/saitoha/libsixel/security/advisories/GHSA-2xgm-4x47-2x2p",
                        "tags": [
                            "exploit"
                        ]
                    }
                ],
                "metrics": [
                    {
                        "other": {
                            "type": "ssvc",
                            "content": {
                                "timestamp": "2026-04-15T13:30:43.489988Z",
                                "id": "CVE-2026-33020",
                                "options": [
                                    {
                                        "Exploitation": "poc"
                                    },
                                    {
                                        "Automatable": "no"
                                    },
                                    {
                                        "Technical Impact": "total"
                                    }
                                ],
                                "role": "CISA Coordinator",
                                "version": "2.0.3"
                            }
                        }
                    }
                ],
                "title": "CISA ADP Vulnrichment",
                "providerMetadata": {
                    "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
                    "shortName": "CISA-ADP",
                    "dateUpdated": "2026-04-15T13:30:47.463Z"
                }
            }
        ]
    }
}