Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
Buffer overflow in drivers/xen/sys-hypervisor.c
The build id returned by HYPERVISOR_xen_version(XENVER_build_id) is neither NUL terminated nor a string.
The first causes a buffer overflow as sprintf in buildid_show will read and copy till it finds a NUL.
00000000 f4 91 51 f4 dd 38 9e 9d 65 47 52 eb 10 71 db 50 |..Q..8..eGR..q.P| 00000010 b9 a8 01 42 6f 2e 32 |…Bo.2| 00000017
So use a memcpy instead of sprintf to have the correct value:
00000000 f4 91 51 f4 dd 00 9e 9d 65 47 52 eb 10 71 db 50 |..Q…..eGR..q.P| 00000010 b9 a8 01 42 |…B| 00000014
(the above have a hack to embed a zero inside and check it’s returned correctly).
This is XSA-485 / CVE-2026-31786
Details
- Affected product:
- AlmaLinux 9.2 ESU , CentOS 8.4 ELS , CentOS 8.5 ELS , CentOS Stream 8 ELS , TuxCare 9.6 ESU
- Affected packages:
- kernel @ 4.18.0 (+4 more)
Fixes
KernelCare state
Live-patch status from KernelCare for each operating system.
| Operating system | Status | Covered kernels |
|---|---|---|
| AlmaLinux 10 | Released |
37 kernels
|
| AlmaLinux 8 | Released |
109 kernels
|
| AlmaLinux 9 | Released |
108 kernels
|
| AlmaLinux 9.2 ESU | Released |
25 kernels
|
| Amazon Linux 2023 | Planned | — |
| CentOS 8 | Released |
21 kernels
|
| CloudLinux OS 7h | Released |
104 kernels
|
| CloudLinux OS 8 | Released |
101 kernels
|
| Debian 11 | Released |
37 kernels
|
| Debian 11 cloud | Released |
17 kernels
|
| Debian 12 | Released |
35 kernels
|
| Debian 13 | Planned | — |
| Oracle Linux 8 | Released |
118 kernels
|
| Oracle Linux 9 | Released |
109 kernels
|
| RHEL 10 | Released |
37 kernels
|
| RHEL 8 | Released |
113 kernels
|
| RHEL 9 | Released |
106 kernels
|
| Rocky Linux 10 | Released |
27 kernels
|
| Rocky Linux 8 | Released |
91 kernels
|
| Rocky Linux 9 | Released |
87 kernels
|