
CVE-2026-80724 PoC + full write-up — Linux kernel ptp/vmclock read-only mapping becomes writable (VM_MAYWRITE). Discovered, reported & fixed by Abdifatah Suruur (suruurism)
CVE-2026-80724 — Linux kernel ptp: vmclock: prevent read-only mappings from becoming writable
Full Proof-of-Concept + Technical Write-up
Security research by Abdifatah Suruur (suruur) — collection of CVE write-ups and PoCs for vulnerabilities discovered independently.
drivers/ptp/ptp_vmclock.cgit clone https://github.com/suruurism/cve-writeups-and-pocs.git
cd cve-writeups-and-pocs/CVE-2026-80724
make
sudo ./vmclock_poc /dev/vmclock0
| Exit Code | Meaning |
|---|
| 0 | WRITE LANDED → system is vulnerable |
| 1 | mprotect refused or write faulted → patched |
| 2 | No vmclock device found |
The ptp_vmclock driver correctly rejects writable mappings of the shared
vmclock ABI page with -EROFS, but leaves VM_MAYWRITE set.
A process that can open /dev/vmclockN can:
mmap() the page as PROT_READmprotect(PROT_READ|PROT_WRITE)This breaks the fundamental read-only contract of the vmclock ABI.
| Path | Description |
|---|---|
CVE-2026-80724/CVE-2026-80724.md | Full technical write-up (root cause, impact, timeline, references) |
CVE-2026-80724/vmclock_poc.c | Working Proof-of-Concept |
CVE-2026-80724/Makefile | Simple build file |
Abdifatah Suruur (suruur / suruurism)
This repository is for educational and research purposes only.
Use the PoC only on systems you own or have explicit permission to test.