I don't think it's plausible OSS-Fuzz could have found this. The backdoor required a build configuration that was not used in OSS-Fuzz.
I'm guessing "Jia Tan" knew this and made changes to XZ's use of OSS-Fuzz for the purposes of cementing their position as the new maintainer of XZ, rather than out of worry OSS-Fuzz would find the backdoor as people have speculated.
I don't think it's plausible OSS-Fuzz could have found this. The backdoor required a build configuration that was not used in OSS-Fuzz.
I'm guessing "Jia Tan" knew this and made changes to XZ's use of OSS-Fuzz for the purposes of cementing their position as the new maintainer of XZ, rather than out of worry OSS-Fuzz would find the backdoor as people have speculated.