stb_image.h (aka the stb image loader) 2.23, as used in libsixel and other products, has an assertion failure in stbi__shiftsigned.
The product contains an assert() or similar statement that can be triggered by an attacker, which leads to an application exit or other behavior that is more severe than necessary.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Stb_image.h | Nothings | 2.23 (including) | 2.23 (including) |
| Libsixel | Ubuntu | bionic | * |
| Libsixel | Ubuntu | disco | * |
| Libsixel | Ubuntu | eoan | * |
| Libsixel | Ubuntu | trusty | * |
| Libsixel | Ubuntu | xenial | * |
While assertion is good for catching logic errors and reducing the chances of reaching more serious vulnerability conditions, it can still lead to a denial of service. For example, if a server handles multiple simultaneous connections, and an assert() occurs in one single connection that causes all other connections to be dropped, this is a reachable assertion that leads to a denial of service.