Vulnerability · Published Oct 8, 2026 · Assigned by GitHub_M

CVE-2026-107733SumatraPDF: Null-pointer dereference in `CmdExec` when no document tab is open

Medium 6.8

In plain English

A medium-severity null pointer dereference in sumatrapdf from sumatrapdfreader. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 5% of all known vulnerabilities).

Severity (CVSS 4.0)6.8Medium

Exploit odds (30 days)0.2%top 95.2% of all CVEs

Exploited in the wildNo reportsCISA SSVC: poc

Attack toolingNoneno public tooling known

Official description

SumatraPDF is a multi-format reader for Windows. In 3.6.1 and earlier, FrameOnCommand() handles CmdExec by passing a null current-tab pointer to RunWithExe(), which dereferences WindowTab::filePath. A local process in the same interactive Windows session, at an integrity level greater than or equal to SumatraPDF's under Windows UIPI, can dispatch CmdExec over DDE or WM_COPYDATA while no document tab is open, causing abrupt process termination and loss of unsaved state. No broader impact is claimed beyond the advisory-supported conditions. No fixed version is available as of this review.

Affected products (as reported)

Vendor	Product	Versions
sumatrapdfreader	sumatrapdf	<= 3.6.1

Weakness: CWE-476 · Vector: CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

References

https://github.com/sumatrapdfreader/sumatrapdf/security/advisories/GHSA-p2ph-2rvm-q37m x_refsource_CONFIRM
https://github.com/sumatrapdfreader/sumatrapdf/commit/013ad659c7de13fa15624d1f8a24e3231c50516b x_refsource_MISC