CVE-2026-121744 Ashlar-Vellum Cobalt XE File Parsing Stack-based Buffer Overflow Remote Code Execution Vulnerability
A malicious XE file opened in Ashlar-Vellum Cobalt can overflow a stack buffer and execute code; Cobalt users should care.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- A user has to click or open something
- Harmful if only installed
- No
- Needs a specific call
- No
- Fix
- None listed
What is CVE-2026-121744?
CVE-2026-121744 is a high-severity memory corruption vulnerability in Ashlar-Vellum Cobalt, published on 12 Nov 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
Ashlar-Vellum Cobalt XE File Parsing Stack-based Buffer Overflow Remote Code Execution Vulnerability. This vulnerability allows remote attackers to execute arbitrary code on affected installations of Ashlar-Vellum Cobalt. User interaction is required to exploit this vulnerability in that the target must visit a malicious page or open a malicious file.
The specific flaw exists within the parsing of XE files. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a stack-based buffer. An attacker can leverage this vulnerability to execute code in the context of the current process. Was ZDI-CAN-28172.
Weakness: CWE-121
Which versions are affected by CVE-2026-121744?
An affected version is exposed as installed. No special setting or call is needed.
How do I fix CVE-2026-121744?
No fix has been published for CVE-2026-121744 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2026-121744 being exploited?
There is no known exploitation of CVE-2026-121744 in the wild and no public exploit code.
Sources
Also known as GHSA-pfhp-6544-jh4j.