bpf: reject BPF_PSEUDO_FUNC reference to the main program

Summary

In the Linux kernel, the following vulnerability has been resolved: bpf: reject BPF_PSEUDO_FUNC reference to the main program fixups.c:jit_subprogs() rewrites BPF_PSEUDO_FUNC loads to contain real function addresses. This function is invoked from bpf_jit_subprogs() only when env->subprog_cnt > 1. Meaning that for any program like below: int main(void *ctx) { void *ptr = main; ... bpf_timer_set_callback(..., ptr); ... } The 'ptr' won't be ever converted to contain an address. In combination with e.g. bpf_timer_set_callback() this would lead to a function call at a bogus address. Instead of complicating the implementation, just assume that no useful program needs main to be a sync or async callback and reject BPF_PSEUDO_FUNC loads for the main subprogram.

Timeline

1. Sep 25, 2026, 10:24 AM UTCCVE published
2. Oct 19, 2026, 9:13 AM UTCRecord last updated

Affected versions

• Linux Linux

  From 69c087ba6225b574afb6e505b72cb75242a3d844 · fixed in c74750dca96f40a1adb9d334f5a3152f44b270c3; From 69c087ba6225b574afb6e505b72cb75242a3d844 · fixed in 314c8caa9cb64ad60c5b969fe9a3e2dcdccf156f; From 69c087ba6225b574afb6e505b72cb75242a3d844 · fixed in 8cb75f7ada25b1cf25f2f74dec3ba649b9064a09; From 69c087ba6225b574afb6e505b72cb75242a3d844 · fixed in 118212417ba0120d99f84154799f8880f07411f4; From 69c087ba6225b574afb6e505b72cb75242a3d844 · fixed in d6c39774ae093c9f7009cc4ae918f18fc1af7ae7; From 69c087ba6225b574afb6e505b72cb75242a3d844 · fixed in 92f0bd0e2b632c6565ac2214a4d7d2ed37e5b9f6; From 69c087ba6225b574afb6e505b72cb75242a3d844 · fixed in 374b2c5561db80fcdd7cdce44af37a49416f61c7

• Linux Linux

  5.13

• KernelLinux

  From 5.13.0 · fixed in 5.15.222; From 5.16.0 · fixed in 6.1.189; From 6.2.0 · fixed in 6.6.158; From 6.7.0 · fixed in 6.12.111; From 6.13.0 · fixed in 6.18.53; From 6.19.0 · fixed in 7.2.7

References 7