# CVE-2026-80671: perf sched: Fix register_pid() overflow, strcpy, and BUG_ON

> An integer overflow and buffer overflow in the Linux kernel perf sched tool allow attackers to execute arbitrary code or cause a denial of service via malicious perf.data files.

- **Severity:** Critical 9.3 (`CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 28 Aug 2026
- **Updated:** 14 Sep 2026
- **Also known as:** AZL-98180, BELL-CVE-2026-80671, DEBIAN-CVE-2026-80671, GHSA-98vx-8r93-84hf, UBUNTU-CVE-2026-80671

## What is CVE-2026-80671?

CVE-2026-80671 is a critical vulnerability in Linux, published on 28 Aug 2026. 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:

perf sched: Fix register_pid() overflow, strcpy, and BUG_ON

register_pid() has several issues when processing untrusted perf.data:

1. Integer overflow: (pid + 1) * sizeof(struct task_desc *) can wrap
   to a small value on 32-bit systems when pid is large (e.g.
   0x40000000), causing realloc to return a tiny buffer followed by
   out-of-bounds writes in the initialization loop.

2. Heap buffer overflow: strcpy(task->comm, comm) copies the
   untrusted comm string into a fixed 20-byte COMM_LEN buffer with
   no length check.

3. BUG_ON on allocation failure: perf.data is untrusted input, so
   allocation failures should be handled gracefully rather than
   killing the process.

4. Realloc of sched->tasks assigned directly back, leaking the old
   pointer on failure; nr_tasks incremented before the realloc,
   leaving corrupted state on failure.

Cap pid at PID_MAX_LIMIT (4194304, matching the kernel's maximum
on 64-bit), replace strcpy with strlcpy, guard against NULL comm,
replace BUG_ON with NULL returns using safe realloc patterns, and
add NULL checks in callers that dereference the result.

## Which versions are affected by CVE-2026-80671?


## How do I fix CVE-2026-80671?

Apply the vendor's patch.

## Is CVE-2026-80671 being exploited?

There is no known exploitation of CVE-2026-80671 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-80671 and fix it if it is affected.

What it is: CVE-2026-80671 is a critical vulnerability in Linux, published on 28 Aug 2026. 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-2026-80671 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-2026-80671/ (Markdown: https://insights.sbomify.com/CVE-2026-80671/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-80671
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-80671
- OSV: https://osv.dev/vulnerability/CVE-2026-80671

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-80671/
Summaries are generated and may contain mistakes; the official description above is the record.