# CVE-2025-68742: bpf: Fix invalid prog->stats access when update_effective_progs fails

> A local attacker can trigger a kernel crash via invalid memory access in BPF stats handling when program updates fail.

- **Severity:** Not scored
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 24 Dec 2025
- **Updated:** 15 Oct 2026
- **Also known as:** AZL-73108, BELL-CVE-2025-68742, DEBIAN-CVE-2025-68742, GHSA-jvhg-r77c-vccf, ROOT-OS-DEBIAN-11-CVE-2025-68742, ROOT-OS-DEBIAN-12-CVE-2025-68742, ROOT-OS-UBUNTU-2204-CVE-2025-68742, ROOT-OS-UBUNTU-2404-CVE-2025-68742, UBUNTU-CVE-2025-68742

## What is CVE-2025-68742?

CVE-2025-68742 is a vulnerability in Linux, published on 24 Dec 2025. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

bpf: Fix invalid prog->stats access when update_effective_progs fails

Syzkaller triggers an invalid memory access issue following fault
injection in update_effective_progs. The issue can be described as
follows:

__cgroup_bpf_detach
  update_effective_progs
    compute_effective_progs
      bpf_prog_array_alloc <-- fault inject
  purge_effective_progs
    /* change to dummy_bpf_prog */
    array->items[index] = &dummy_bpf_prog.prog

---softirq start---
__do_softirq
  ...
    __cgroup_bpf_run_filter_skb
      __bpf_prog_run_save_cb
        bpf_prog_run
          stats = this_cpu_ptr(prog->stats)
          /* invalid memory access */
          flags = u64_stats_update_begin_irqsave(&stats->syncp)
---softirq end---

  static_branch_dec(&cgroup_bpf_enabled_key[atype])

The reason is that fault injection caused update_effective_progs to fail
and then changed the original prog into dummy_bpf_prog.prog in
purge_effective_progs. Then a softirq came, and accessing the members of
dummy_bpf_prog.prog in the softirq triggers invalid mem access.

To fix it, skip updating stats when stats is NULL.

## Which versions are affected by CVE-2025-68742?


## How do I fix CVE-2025-68742?

Apply the vendor's patch.

## Is CVE-2025-68742 being exploited?

There is no known exploitation of CVE-2025-68742 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-68742 and fix it if it is affected.

What it is: CVE-2025-68742 is a vulnerability in Linux, published on 24 Dec 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2025-68742 in the wild and no public exploit code.

Affected product: Linux. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-68742/ (Markdown: https://insights.sbomify.com/CVE-2025-68742/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-68742
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-68742
- OSV: https://osv.dev/vulnerability/CVE-2025-68742

---
From sbomify Insights: https://insights.sbomify.com/CVE-2025-68742/
Summaries are generated and may contain mistakes; the official description above is the record.