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.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
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.
Sources
Also known as AZL-98180, BELL-CVE-2026-80671, DEBIAN-CVE-2026-80671, GHSA-98vx-8r93-84hf, UBUNTU-CVE-2026-80671.