A use after free vulnerability exists in curl <v8.1.0 in the way libcurl offers a feature to verify an SSH servers public key using a SHA 256 hash. When this check fails, libcurl would free the memory for the fingerprint before it returns an error message containing the (now freed) hash. This flaw risks inserting sensitive heap-based data into the error message that might be shown to users or otherwise get leaked and revealed.
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory “belongs” to the code that operates on the new pointer.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Curl | Haxx | * | 8.1.0 (excluding) |
| JBoss Core Services for RHEL 8 | RedHat | jbcs-httpd24-curl-0:8.2.1-1.el8jbcs | * |
| JBoss Core Services on RHEL 7 | RedHat | jbcs-httpd24-curl-0:8.2.1-1.el7jbcs | * |
| Text-Only JBCS | RedHat | jbcs-httpd24-curl | * |
| Curl | Ubuntu | trusty | * |
| Curl | Ubuntu | upstream | * |
| Curl | Ubuntu | xenial | * |