Kernel crash via undersized PCI BAR0 mapping
Published Sep 25, 2026 · Updated Sep 25, 2026
Out-of-bounds I/O write in the Linux cirrus-qemu driver allows attackers to crash the kernel through an undersized PCI BAR0. During cirrus_pci_probe(), the driver maps BAR0 without checking that it is at least 4 MB, while later framebuffer validation assumes the full 4 MB and drm_fb_memcpy() writes beyond the mapping. The crash requires a sub-4 MB BAR0 to be presented and bound to the driver, followed by a display-plane update; the published reproducer identifies a VM-host peripheral trigger rather than a network or unprivileged path.
Summary
What happened
Out-of-bounds I/O write in the Linux cirrus-qemu driver allows attackers to crash the kernel through an undersized PCI BAR0. During cirrus_pci_probe(), the driver maps BAR0 without checking that it is at least 4 MB, while later framebuffer validation assumes the full 4 MB and drm_fb_memcpy() writes beyond the mapping. The crash requires a sub-4 MB BAR0 to be presented and bound to the driver, followed by a display-plane update; the published reproducer identifies a VM-host peripheral trigger rather than a network or unprivileged path.
The record
- CVE
- CVE-2026-98142
- Published
- Sep 25, 2026
- Updated
- Sep 25, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- T1499.004
- Attack vector
- local
- Privileges
- admin
Timeline
How it unfolded
- Sep 25, 2026CVE publishedPublication date reported by the CVE source.
- Sep 25, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=5.2
- Affected versionversion=ab3e023b1b4c9887c9f0f761b47f3f0516bd3434 <0b5084a1f070ad1fc34e11945644ae034bbc774c
- Affected versionversion=ab3e023b1b4c9887c9f0f761b47f3f0516bd3434 <144f51cd0ccc3ad47a6099917b7bb535611fb18f
- Affected versionversion=ab3e023b1b4c9887c9f0f761b47f3f0516bd3434 <26bd90c886218f36c9adeab206b0e27b4384e2f6
- Affected versionversion=ab3e023b1b4c9887c9f0f761b47f3f0516bd3434 <92312d333bf700798f92f30406c721bce87506f3
What conditions does exploitation require?
What is affected?
Published CVSS scores
No CVSS assessment is available in this record.
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Activity data is delayed. The latest report is Sep 28, 2026.
Weakness, pattern, technique
Public exploit references
- syzbot C reproducer for cirrus_primary_plane_helper_atomic_update page faultproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Get started to see how Hinoki identifies affected software and validates exploitability in your environment.
Get started