The verifier has had bugs in the past. Here's six of them from 2017: https://www.openwall.com/lists/oss-security/2017/12/23/2 https://www.openwall.com/lists/oss

The verifier has had bugs in the past. Here's six of them from 2017: https://www.openwall.com/lists/oss-security/2017/12/23/2 https://www.openwall.com/lists/oss-security/2017/12/23/2 one of which was discovered to have an incomplete fix in 2018: https://crbug.com/project-zero/1686 https://crbug.com/project-zero/1686 https://medium.com/@tyanir/understanding-bpf-check-alu-op-vulnerability-cve-2017-16995-3eb3017f598a https://medium.com/@tyanir/understanding-bpf-check-alu-op-vu... has a longer description of one of them - namely, you can convince the verifier that a certain part of the program is dead code and therefore doesn't need to be verified when it does, and thereby get arbitrary unverified eBPF into the kernel.