CVE-2026-107738: medium-severity vulnerability in sumatrapdfreader sumatrapdf
SumatraPDF: Untrusted binary record offset used without lower-bound validation
Published
10Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 6.8
exploitation probability
—
observed exploitation
nono source reports it
SumatraPDF is a multi-format reader for Windows. In 3.6.1 and earlier, ChmFile::GetCharZ() narrows file-controlled unsigned string offsets from /#WINDOWS and /#IVB to signed integers without a lower-bound check. An offset that becomes negative can make the function read before the /#STRINGS buffer, causing deterministic application termination. No broader impact is claimed beyond the advisory-supported conditions. No fixed version is available as of this review.
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Affected products
sumatrapdfreader · sumatrapdfRelated CVEs — sumatrapdfreader sumatrapdf
In the same product, most dangerous first.
CVE-2026-25961HIGHSumatraPDF Update MITM -> Arbitrary Code ExecutionEPSS 0.5%CVE-2026-25920MEDIUMSumatraPDF has a heap out-of-bounds read in MOBI HuffDic decompressorEPSS 0.3%CVE-2026-25880HIGHUntrusted Search Path in SumatraPDF Reader (explorer.exe on Windows)EPSS 0.2%CVE-2026-23951MEDIUMSumatraPDF's Integer Underflow in PalmDbReader Leads to CrashEPSS 0.2%CVE-2026-23512HIGHSumatraPDF has an Untrusted Search Path in sumatrapdf/src/AppTools.cppEPSS 0.2%CVE-2026-55586MEDIUMSumatraPDF: Heap out-of-bounds write in vendored CHMLib LZX Huffman table construction reachable from crafted CHM filesEPSS 0.2%