NaCl in 2015 allowed the CLFLUSH instruction, making rowhammer attacks possible.
Source: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2015-0565
Reference (s):
- https://googleprojectzero.blogspot.com/2015/03/exploiting-dram-rowhammer-bug-to-gain.html
- https://www.exploit-db.com/exploits/36310/
- https://www.exploit-db.com/exploits/36311/