Dia · Dia · CVE-2026-77658
**Name of the Vulnerable Software and Affected Versions**
Dia versions prior to 0.98.1
**Description**
A stack-based buffer overflow occurs when processing Network Bus objects from XML project files. The `bus load()` function reads the `bus handles` attribute using `attribute num data()` without validating an upper bound. When a bus handle is moved, the `bus handle moved()` function uses `g alloca()` to allocate two temporary arrays on the stack based on the `num handles` variable. An attacker can provide an excessively large value for `num handles` in a malicious .dia file, causing the application to exceed the thread stack limit, leading to a SIGSEGV (segmentation fault) and potential corruption of the stack frame or return address. This same pattern is also present in `objects/Misc/tree.c` and may affect Tree objects. Exploitation occurs when a user opens a malicious file and manipulates a bus handle.
**Recommendations**
At the moment, there is no information about a newer version that contains a fix for this vulnerability.