A double free vulnerability exists in libcurl <8.0.0 when sharing HSTS data between separate handles. This sharing was introduced without considerations for do this sharing across separate threads but there was no indication of this fact in the documentation. Due to missing mutexes or thread locks, two threads sharing the same HSTS data could end up doing a double-free or use-after-free.
Weakness
The product calls free() twice on the same memory address.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Libcurl | Haxx | 7.88.0 (including) | 7.88.0 (including) |
| Libcurl | Haxx | 7.88.1 (including) | 7.88.1 (including) |
| Curl | Ubuntu | lunar | * |
| Curl | Ubuntu | trusty | * |
| Curl | Ubuntu | upstream | * |
| Curl | Ubuntu | xenial | * |