Overview
About vulnerability
In the Linux kernel, the following vulnerability has been resolved:
fbcon: fix integer overflow in fbcon_do_set_font
Fix integer overflow vulnerabilities in fbcon_do_set_font() where font size calculations could overflow when handling user-controlled font parameters.
The vulnerabilities occur when:
- CALC_FONTSZ(h, pitch, charcount) performs h * pith * charcount multiplication with user-controlled values that can overflow.
- FONT_EXTRA_WORDS * sizeof(int) + size addition can also overflow
- This results in smaller allocations than expected, leading to buffer overflows during font data copying.
Add explicit overflow checking using check_mul_overflow() and check_add_overflow() kernel helpers to safety validate all size calculations before allocation.
Details
- Affected product:
- AlmaLinux 9.2 ESU , Amazon Linux 2 ELS , CentOS 8.4 ELS , CentOS 8.5 ELS , CentOS Stream 8 ELS , Oracle Linux 7 ELS , TuxCare 9.6 ESU , TuxCare 9.8 ESU , Ubuntu 16.04 ELS , Ubuntu 18.04 ELS , Ubuntu 20.04 ELS
- Affected packages:
- kernel-uek @ 5.4.17 (+11 more)
Fixes
KernelCare state
Live-patch status from KernelCare for each operating system.
| Operating system | Status | Covered kernels |
|---|---|---|
| AlmaLinux 9.2 ESU | Released |
17 kernels
|
| AlmaLinux 9.6 ESU | Released |
9 kernels
|
| Amazon Linux 2023 | Ready For Release | — |
| Debian 11 | Released |
36 kernels
|
| Debian 11 cloud | Released |
16 kernels
|
| Debian 12 | Released |
31 kernels
|
| Debian 13 | Planned | — |
| Oracle Linux 7 UEK 6 | Released |
112 kernels
|
| Oracle Linux 8 UEK 6 | Released |
138 kernels
|
| Oracle Linux 8 UEK 7 | Released |
81 kernels
|
| Oracle Linux 9 UEK 7 | Released |
81 kernels
|
| Proxmox VE 7 5.15 | Released |
47 kernels
|
| Ubuntu 20.04 HWE AWS | Released |
57 kernels
|
| Ubuntu 20.04 HWE Azure | Released |
40 kernels
|
| Ubuntu 22.04 | Released |
88 kernels
|
| Ubuntu 22.04 AWS | Released |
79 kernels
|
| Ubuntu 22.04 Azure | Released |
73 kernels
|
| Ubuntu 24.04 | Released |
39 kernels
|
| Ubuntu 24.04 AWS | Planned | — |