CVE-2026-115758: high-severity vulnerability in sumatrapdfreader sumatrapdf
SumatraPDF: TLS hostname validation disabled in `HttpGet()`
Published
E-mail alert when it lands in KEV, gets a public PoC or its score goes up.
21Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 8.2epss 0.1%
SumatraPDF is a multi-format reader for Windows. In version 3.6.1 and earlier, HttpGet() in src/base/Http_win.cpp unconditionally passes INTERNET_FLAG_IGNORE_CERT_CN_INVALID to WinINet, disabling hostname matching for HTTPS update metadata and crash-symbol requests while retaining certificate-chain validation. A network-positioned attacker with a Windows-trusted certificate for an attacker-controlled domain can impersonate the project's update host, inject promo text and a clickable URL before update metadata validation, and provide an attacker-controlled archive to ExtractSymbols(). Installer replacement is not directly possible because HttpGetToFile() validates TLS and MaybeStartUpdateDownload() restricts the download host. No fixed version is available as of this review.
CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:N/VI:H/VA:N/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 0.4%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-2026-23512HIGHSumatraPDF has an Untrusted Search Path in sumatrapdf/src/AppTools.cppEPSS 0.2%CVE-2026-23951MEDIUMSumatraPDF's Integer Underflow in PalmDbReader Leads to CrashEPSS 0.2%CVE-2026-26054MEDIUMSumatraPDF: Heap out-of-bounds read in MOBI header parser.EPSS 0.2%