CVE-2026-41034 Information disclosure in ONLYOFFICE DocumentServer
An untrusted pointer dereference in XLS processing allows attackers to leak information and bypass ASLR in ONLYOFFICE DocumentServer.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-41034?
CVE-2026-41034 is a medium-severity vulnerability in Ascensio ONLYOFFICE DocumentServer, published on 16 Apr 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
ONLYOFFICE DocumentServer before 9.3.0 has an untrusted pointer dereference in XLS processing/conversion (via pictFmla.cbBufInCtlStm and other vectors), leading to an information leak and ASLR bypass.
Weakness: CWE-125
Which versions are affected by CVE-2026-41034?
How do I fix CVE-2026-41034?
No fix has been published for CVE-2026-41034 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-41034 being exploited?
There is no known exploitation of CVE-2026-41034 in the wild and no public exploit code.
Sources
Also known as GHSA-28j6-w975-f9x7.