CVE-2024-58237: bpf: consider that tail calls invalidate packet pointers

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2025-05-05 · updated 2026-10-15
Weakness: CWE-476

Description

In the Linux kernel, the following vulnerability has been resolved: bpf: consider that tail calls invalidate packet pointers Tail-called programs could execute any of the helpers that invalidate packet pointers. Hence, conservatively assume that each tail call invalidates packet pointers. Making the change in bpf_helper_changes_pkt_data() automatically makes use of check_cfg() logic that computes 'changes_pkt_data' effect for global sub-programs, such that the following program could be rejected: int tail_call(struct __sk_buff *sk) { bpf_tail_call_static(sk, &jmp_table, 0); return 0; } SEC("tc") int not_safe(struct __sk_buff *sk) { int *p = (void *)(long)sk->data; ... make p valid ... tail_call(sk); *p = 42; /* this is unsafe */ ... } The tc_bpf2bpf.c:subprog_tc() needs change: mark it as a function that can invalidate packet pointers. Otherwise, it can't be freplaced with tailcall_freplace.c:entry_freplace() that does a tail call.

Affected products

Linux kernel: from 5.6 before 6.6.90; from 6.7 before 6.12.9; 6.13-rc1, 6.13-rc2 — fixed in 6.12.9, 6.6.90

How to fix

Upgrade to a fixed version: Linux kernel 6.12.9, 6.6.90. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2024-58237 or the next vulnerability affects your stack