CVE-2026-26399 Use after free in n/a
A stack-use-after-return in the Arduino_Core_STM32 library allows attackers to cause memory corruption via dangling pointers in timer interrupts.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-26399?
CVE-2026-26399 is a medium-severity use after free vulnerability in n/a, published on 20 Apr 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
A stack-use-after-return issue exists in the Arduino_Core_STM32 library prior to version 1.7.0. The pwm_start() function allocates a TIM_HandleTypeDef structure on the stack and passes its address to HAL initialization routines, where it is stored in a global timer handle registry. After the function returns, interrupt service routines may dereference this dangling pointer, resulting in memory corruption.
Weakness: CWE-562
Which versions are affected by CVE-2026-26399?
How do I fix CVE-2026-26399?
No fix has been published for CVE-2026-26399 yet. Limit exposure of the affected software until one is available.
Upgrade to the fixed version. These bugs are found with fuzzing and sanitisers and avoided by memory-safe languages. More about Use after free.
Is CVE-2026-26399 being exploited?
There is no known exploitation of CVE-2026-26399 in the wild and no public exploit code.
Public exploit code: 1 proofs of concept on GitHub.
Sources
Also known as GHSA-vxch-4r45-jhw9, UBUNTU-CVE-2026-26399.