fmtlib version prior to version 4.1.0 (before commit 0555cea5fc0bf890afe0071a558e44625a34ba85) contains a Memory corruption (SIGSEGV), CWE-134 vulnerability in fmt::print() library function that can result in Denial of Service. This attack appear to be exploitable via Specifying an invalid format specifier in the fmt::print() function results in a SIGSEGV (memory corruption, invalid write). This vulnerability appears to have been fixed in after commit 8cf30aa2be256eba07bb1cefb998c52326e846e7.
The product uses a function that accepts a format string as an argument, but the format string originates from an external source.
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Fmt | Fmt | * | 4.1.0 (excluding) |
| Fmtlib | Ubuntu | bionic | * |
| Fmtlib | Ubuntu | cosmic | * |
When an attacker can modify an externally-controlled format string, this can lead to buffer overflows, denial of service, or data representation problems. It should be noted that in some circumstances, such as internationalization, the set of format strings is externally controlled by design. If the source of these format strings is trusted (e.g. only contained in library files that are only modifiable by the system administrator), then the external control might not itself pose a vulnerability.