Описание
In the Linux kernel, the following vulnerability has been resolved:
fbdev: bitblit: bound-check glyph index in bit_putcs*
bit_putcs_aligned()/unaligned() derived the glyph pointer from the
character value masked by 0xff/0x1ff, which may exceed the actual font's
glyph count and read past the end of the built-in font array.
Clamp the index to the actual glyph count before computing the address.
This fixes a global out-of-bounds read reported by syzbot.
A flaw was found in the Linux kernel. A local attacker can exploit this vulnerability by providing a specially crafted font glyph index to the bitblit component. This can lead to an out-of-bounds read, potentially resulting in information disclosure or a denial of service.
Отчет
This vulnerability is rated Moderate because it requires an authenticated local user with access to render text to the framebuffer console, and successful exploitation is limited to information disclosure or causing a system crash rather than arbitrary code execution. On typical Red Hat Enterprise Linux server deployments, systems operate headless or without active graphical framebuffer consoles, substantially reducing real-world exposure. The flaw cannot be exploited remotely without an established local access vector.
Меры по смягчению последствий
To mitigate this issue, prevent the fbdev kernel module from loading if it is not required for system operation. Create a file named /etc/modprobe.d/disable-fbdev.conf with the following content:
After creating the file, regenerate the initramfs using dracut -f -v and reboot the system for the changes to take effect. This mitigation may impact systems that rely on fbdev for console display or specific graphics hardware, requiring careful evaluation before implementation.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 6 | kernel | Not affected | ||
| Red Hat Enterprise Linux 7 | kernel | Not affected | ||
| Red Hat Enterprise Linux 7 | kernel-rt | Not affected | ||
| Red Hat Enterprise Linux 9 | kernel-rt | Affected | ||
| Red Hat Enterprise Linux 10 | kernel | Fixed | RHSA-2026:2282 | 09.02.2026 |
| Red Hat Enterprise Linux 10.0 Extended Update Support | kernel | Fixed | RHSA-2026:1727 | 02.02.2026 |
| Red Hat Enterprise Linux 8 | kernel-rt | Fixed | RHSA-2026:1661 | 02.02.2026 |
| Red Hat Enterprise Linux 8 | kernel | Fixed | RHSA-2026:1662 | 02.02.2026 |
| Red Hat Enterprise Linux 8.2 Advanced Update Support | kernel | Fixed | RHSA-2026:2664 | 12.02.2026 |
| Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support | kernel | Fixed | RHSA-2026:3360 | 25.02.2026 |
Показывать по
Дополнительная информация
Статус:
EPSS
7.1 High
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: fbdev: bitblit: bound-check glyph index in bit_putcs* bit_putcs_aligned()/unaligned() derived the glyph pointer from the character value masked by 0xff/0x1ff, which may exceed the actual font's glyph count and read past the end of the built-in font array. Clamp the index to the actual glyph count before computing the address. This fixes a global out-of-bounds read reported by syzbot.
In the Linux kernel, the following vulnerability has been resolved: fbdev: bitblit: bound-check glyph index in bit_putcs* bit_putcs_aligned()/unaligned() derived the glyph pointer from the character value masked by 0xff/0x1ff, which may exceed the actual font's glyph count and read past the end of the built-in font array. Clamp the index to the actual glyph count before computing the address. This fixes a global out-of-bounds read reported by syzbot.
In the Linux kernel, the following vulnerability has been resolved: f ...
In the Linux kernel, the following vulnerability has been resolved: fbdev: bitblit: bound-check glyph index in bit_putcs* bit_putcs_aligned()/unaligned() derived the glyph pointer from the character value masked by 0xff/0x1ff, which may exceed the actual font's glyph count and read past the end of the built-in font array. Clamp the index to the actual glyph count before computing the address. This fixes a global out-of-bounds read reported by syzbot.
EPSS
7.1 High
CVSS3