# CVE-2026-80670: perf tools: Use perf_env__get_cpu_topology() in machine__resolve()

> A crafted perf.data file triggers an out-of-bounds heap read in Linux perf tools, potentially leaking memory or causing a crash.

- **Severity:** Critical 9.1 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 28 Aug 2026
- **Updated:** 29 Aug 2026
- **Also known as:** AZL-98087, BELL-CVE-2026-80670, DEBIAN-CVE-2026-80670, GHSA-wc4v-22m8-hj35, UBUNTU-CVE-2026-80670

## What is CVE-2026-80670?

CVE-2026-80670 is a critical memory corruption vulnerability in Linux, published on 28 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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

perf tools: Use perf_env__get_cpu_topology() in machine__resolve()

machine__resolve() accesses env->cpu[al->cpu].socket_id after checking
al->cpu >= 0 and env->cpu != NULL, but without validating al->cpu
against env->nr_cpus_avail.  Since al->cpu comes from the untrusted
perf.data sample, a crafted file with a large CPU index causes an
out-of-bounds heap read.

Use perf_env__get_cpu_topology() which validates both NULL and bounds.
Also bounds-check al->cpu before the cast to struct perf_cpu (int16_t):
without this, values like 65536 silently truncate to 0, bypassing the
accessor's internal check and returning CPU 0's topology.

## Which versions are affected by CVE-2026-80670?


## How do I fix CVE-2026-80670?

Apply the vendor's patch.

## Is CVE-2026-80670 being exploited?

There is no known exploitation of CVE-2026-80670 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-80670 and fix it if it is affected.

What it is: CVE-2026-80670 is a critical memory corruption vulnerability in Linux, published on 28 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-80670 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-2026-80670/ (Markdown: https://insights.sbomify.com/CVE-2026-80670/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-80670
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-80670
- OSV: https://osv.dev/vulnerability/CVE-2026-80670

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-80670/
Summaries are generated and may contain mistakes; the official description above is the record.