CVE-2026-80671
Received Received - Intake

Integer Overflow and Heap Buffer Overflow in Linux Kernel perf sched

Vulnerability report for CVE-2026-80671, including description, CVSS score, EPSS score, affected products, exploitability, helpful resources, and attack-flow context.

Publication date: 2026-08-28

Last updated on: 2026-08-28

Assigner: kernel.org

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.

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Meta Information

Published
2026-08-28
Last Modified
2026-08-28
Generated
2026-08-28
AI Q&A
2026-08-28
EPSS Evaluated
N/A
NVD
EUVD

Affected Vendors & Products

Showing 1 associated CPE
Vendor Product Version / Range
linux linux_kernel *

Helpful Resources

Exploitability

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CWE ID Description
CWE-UNKNOWN

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Executive Summary

This vulnerability in the Linux kernel's perf sched component involves multiple issues when processing untrusted perf.data files. It includes an integer overflow in register_pid() that can cause out-of-bounds writes, a heap buffer overflow from unchecked strcpy copying into a fixed-size buffer, improper handling of allocation failures with BUG_ON, and memory leaks from incorrect realloc usage. The fix involves capping PID values, replacing unsafe functions, and adding proper error handling.

Detection Guidance

This vulnerability is specific to the Linux kernel's perf tool and requires local system access to detect. Check if your kernel version is affected by running uname -a. If your kernel is older than the patched version, the vulnerability may exist. Monitor system logs for crashes or errors related to perf sched or register_pid.

Impact Analysis

An attacker could exploit this to crash the system, execute arbitrary code with kernel privileges, or leak sensitive information by crafting malicious perf.data files. Systems running unpatched Linux kernels are vulnerable if perf tools process untrusted data.

Mitigation Strategies

Update your Linux kernel to the latest stable version that includes the fix for CVE-2026-80671. Avoid using perf sched on untrusted perf.data files until patched. If immediate patching is not possible, restrict access to perf tools for untrusted users to reduce exposure.

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