CVE-2026-25920
Medium
Description
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.
SeverityMedium
CVSS5.5
Exploit probability—
ProductSumatrapdf
PublishedFeb 9, 2026
First seenFeb 9, 2026
Weakness typeCWE-125Out-of-bounds read
How to fix
Sources list no fixed version or patch link for this vulnerability.
Affected products
| Product | Affected versions | Fixed in |
|---|---|---|
| sumatrapdfreader sumatrapdf | v ≤ 3.5.2 | — |
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