CVE-2026-80724: Linux kernel · ptp: vmclock: prevent read-only mappings from becoming writable
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 8.8 High.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 7% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 28 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A fix is available that clears the VM_MAYWRITE flag on read-only mappings in the vmclock interface to prevent writable upgrades. Users should apply the official Linux kernel updates that address CVE-2026-80724. Since this is a kernel-level vulnerability, upgrading to patched kernel versions is the recommended remediation.
Description
A vulnerability in the Linux kernel's ptp vmclock interface allows a read-only memory mapping to be upgraded to writable, enabling a guest to corrupt host timekeeping data. This occurs because vmclock_miscdev_mmap() rejects writable mappings but leaves VM_MAYWRITE set, permitting mprotect() to escalate permissions. The issue has been resolved by clearing VM_MAYWRITE on the read-only path to prevent writable upgrades.
References
- nvd.nist.gov/vuln/detail/CVE-2026-80724 (opens in a new tab)
- git.kernel.org/stable/c/2496e141827102d6af512950057d402a2cfb2bfc (opens in a new tab)
- git.kernel.org/stable/c/2e596e7814ba38cdc129991058b6c254ed37cb11 (opens in a new tab)
- git.kernel.org/stable/c/5b4f2bec7bea6c04084d720d731bedee7caf878d (opens in a new tab)
- git.kernel.org/stable/c/a5edadbae57e2298a56cf7a4e774a027905a331f (opens in a new tab)
- ubuntu.com/security/CVE-2026-80724 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-80724 (opens in a new tab)
- git.kernel.org/linus/a5edadbae57e2298a56cf7a4e774a027905a331f (opens in a new tab)
- git.kernel.org/stable/c/0ce59c4148ecd1520c5592a63bb3c8991ee2d326 (opens in a new tab)
- git.kernel.org/stable/c/3f5677d2f817355147337f0453174c7bb0f3b66a (opens in a new tab)
- suse.com/support/security/rating/ (opens in a new tab)
- ftp.suse.com/pub/projects/security/csaf/opensuse-su-2026_11703-1.json (opens in a new tab)
- suse.com/security/cve/CVE-2026-80724/ (opens in a new tab)