SumatraPDF is a multi-format reader for Windows. In 3.5.2 and earlier, a heap out-of-bounds read vulnerability exists in SumatraPDF's MOBI HuffDic decompressor. The bounds check in AddCdicData() only validates half the range that DecodeOne() actually accesses. Opening a crafted .mobi file can read nearly (1 << codeLength) bytes beyond the CDIC dictionary buffer, leading to a crash.
{
"cwe_ids": [
"CWE-125"
],
"cna_assigner": "GitHub_M",
"osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/25xxx/CVE-2026-25920.json"
}[
{
"id": "CVE-2026-25920-9a701750",
"target": {
"function": "HuffDicDecompressor::SetHuffData",
"file": "src/MobiDoc.cpp"
},
"signature_version": "v1",
"source": "https://github.com/sumatrapdfreader/sumatrapdf/commit/12b6887e9dfff874fe8749bab1bdc53d4ff075b3",
"signature_type": "Function",
"digest": {
"function_hash": "117232748217294490266174539146530574947",
"length": 838.0
},
"deprecated": false
},
{
"id": "CVE-2026-25920-e3fc5624",
"target": {
"function": "HuffDicDecompressor::AddCdicData",
"file": "src/MobiDoc.cpp"
},
"signature_version": "v1",
"source": "https://github.com/sumatrapdfreader/sumatrapdf/commit/12b6887e9dfff874fe8749bab1bdc53d4ff075b3",
"signature_type": "Function",
"digest": {
"function_hash": "287350018242290791815942785293087108917",
"length": 736.0
},
"deprecated": false
},
{
"id": "CVE-2026-25920-e5bbf2fb",
"target": {
"file": "src/MobiDoc.cpp"
},
"signature_version": "v1",
"source": "https://github.com/sumatrapdfreader/sumatrapdf/commit/12b6887e9dfff874fe8749bab1bdc53d4ff075b3",
"signature_type": "Line",
"digest": {
"line_hashes": [
"298600831982538125963483751285307927202",
"60359313055809950785221283734856490973",
"130352140609533347702064622006691316427",
"243357575680573494118927259087660144105",
"10603795066347093376650904837710558042",
"47245944678176726615706817976194915650",
"110682252844980296563670685921481200219",
"317370050401019544382990563854595922129"
],
"threshold": 0.9
},
"deprecated": false
}
]
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-25920.json"
"2026-04-12T20:23:14Z"