The researchers found five different vulnerabilities. The one that can most unambiguously not be called anything besides a backdoor (internally reducing what were believed to be 80-bit keys down to 32 bits) was specific to TEA1, the export cipher for use outside of Europe and the US, but the other vulnerabilities applied to other ciphers also.

The homepage for the research is https://www.midnightblue.nl/tetraburst