Yes, this particular incident.
https://en.wikipedia.org/wiki/XZ_Utils_backdoor
In February 2024, a malicious backdoor was introduced to the Linux build of the xz utility within the liblzma library in versions 5.6.0 and 5.6.1 by an account using the name “Jia Tan”.[b][4] The backdoor gives an attacker who possesses a specific Ed448 private key remote code execution through OpenSSH on the affected Linux system. The issue has been given the Common Vulnerabilities and Exposures number CVE-2024-3094 and has been assigned a CVSS score of 10.0, the highest possible score.[5]
Microsoft employee and PostgreSQL developer Andres Freund reported the backdoor after investigating a performance regression in Debian Sid.[8] Freund noticed that SSH connections were generating an unexpectedly high amount of CPU usage as well as causing errors in Valgrind,[9] a memory debugging tool.[10]
There doesn’t need to be any evidence. This is something that is impossible to prove one way or the other, like Last Thursdayism.