CVE-2026-107737
SumatraPDF CHM `its://` signed index causes an out-of-bounds object lookup
CVSS Score
0.0
EPSS Score
0.0%
EPSS Percentile
0th
SumatraPDF is a multi-format reader for Windows. In 3.6.1 and earlier, and in pre-release 3.7.0.20369 when WebView2 is absent or cannot initialize, ParseProtoUrl() accepts the signed host component of an its:// URL and FindHtmlWindowById() uses it directly as an index into gHtmlWindows. Opening a crafted CHM through the IE fallback backend with a negative or otherwise out-of-range window identifier can cause an out-of-bounds pointer read followed by an invalid object callback dereference and process termination. No fixed version is available as of this review.
| CWE | CWE-129 |
| Vendor | sumatrapdfreader |
| Product | sumatrapdf |
| Published | Oct 8, 2026 |
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Affected Versions
sumatrapdfreader / sumatrapdf
<= 3.6.1