CVE-2026-33020 Detail
Undergoing Enrichment
This CVE record is currently being enriched by team members, this process results in the association of reference link tags, CVSS, CWE, and CPE applicability statement data Descriptionlibsixel 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. This issue has been fixed in version 1.8.7-r1. Metrics
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CVSS 4.0 Severity and Vector Strings:
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Quick InfoCVE Dictionary Entry:CVE-2026-33020 NVD Published Date: 04/14/2026 NVD Last Modified: 04/17/2026 Source: GitHub, Inc. |
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