CVE-2026-107732 in SumatraPDF
Summary
by MITRE • 10/09/2026
SumatraPDF is a multi-format reader for Windows. In 3.6.1 and earlier, untrusted document paths and PDF link targets are interpolated into notification text that ParseTip() interprets as trusted tip markup. When a user clicks an injected link, ExecuteTipLink() dispatches its CmdExec command and can execute an attacker-selected local program in the user's context. No broader impact is claimed beyond the advisory-supported conditions. No fixed version is available as of this review.
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Analysis
by VulDB Data Team • 10/09/2026
SumatraPDF serves as a widely utilized multi-format document viewer for Windows operating systems, supporting various file types including PDF, EPUB, and MOBI. The vulnerability identified in versions 3.6.1 and earlier centers on an improper neutralization of special elements used in command strings, specifically within the application's tooltip rendering engine. This flaw allows untrusted data to be interpreted as executable commands under specific conditions involving document paths and embedded PDF link targets.
The technical root cause lies in how the ParseTip function processes text intended for display as tooltips or status bar notifications. When a user hovers over certain elements, such as hyperlinks within a PDF document or file path indicators, SumatraPDF constructs notification text that includes these untrusted inputs. Instead of strictly treating this input as plain text to be displayed, the application's internal parser interprets specific syntax patterns as trusted tip markup commands. This misinterpretation creates a pathway for command injection where attacker-controlled data is not properly sanitized or escaped before being passed to subsequent execution handlers.
The operational impact becomes critical when a user interacts with these maliciously crafted elements. Specifically, if an untrusted document path or PDF link target contains injected code that mimics valid tip markup commands, the ExecuteTipLink function may dispatch this content as a CmdExec command. This results in the arbitrary execution of local programs selected by the attacker within the security context of the currently logged-in user. The severity is heightened because it requires only user interaction, such as clicking or hovering over specific links, rather than complex exploitation chains or privilege escalation techniques beyond what is already granted to the application process.
This vulnerability aligns with CWE-78 Improper Neutralization of Special Elements used in an OS Command and CWE-20 Improvement of Error Handling and Input Validation. From a threat intelligence perspective, it maps to ATT&CK technique T1059 Command and Scripting Interpreter, as it enables the execution of arbitrary commands through script-like injection within a legitimate application interface. The attack vector is primarily local or remote depending on how the malicious document is delivered, but exploitation relies heavily on social engineering elements where the victim must interact with the compromised content.
Mitigation strategies are currently limited due to the absence of an official fixed version as noted in available advisories. Users should exercise extreme caution when opening PDF documents from untrusted sources or those containing embedded links and file path references. Disabling JavaScript execution within SumatraPDF, if possible through configuration settings, may reduce the attack surface by preventing some forms of automated interaction. Additionally, employing application whitelisting solutions can help prevent unauthorized programs from executing even if they are triggered via this vulnerability. Organizations should consider alternative PDF readers that have implemented robust input validation and neutralization practices for external data inputs until a patched version is released by the vendor.