CVE-2026-107735 SumatraPDF: `sumatrapdfrestrict.ini` never revokes any permission (fail-open policy initialization)
Attackers can bypass SumatraPDF security restrictions by exploiting a fail-open policy initialization flaw when using the sumatrapdfrestrict.ini configuration file.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Fix
- None listed
What is CVE-2026-107735?
CVE-2026-107735 is a medium-severity vulnerability in sumatrapdfreader sumatrapdf, published on 8 Oct 2026. It can only be exploited from the same machine or local network, and only if a user opens a file or follows a link.
Official description
SumatraPDF is a multi-format reader for Windows. In 3.6.1 and earlier, InitializePolicies() starts the sumatrapdfrestrict.ini path with gPolicyRestrictions set to Perm::All and only ORs permission bits, so the INI file never revokes permissions. Deploying SumatraPDF with this INI file, including a malformed file or zero-valued permission settings, can silently bypass configured disk, network, printing, registry, clipboard, preference, and fullscreen restrictions. The -restrict command-line path works correctly and is not affected. No fixed version is available as of this review.
Weakness: CWE-636
Which versions are affected by CVE-2026-107735?
How do I fix CVE-2026-107735?
No fix has been published for CVE-2026-107735 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-107735 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-107735 exists.
Sources
Also known as GHSA-crhm-w5qr-wjj4.