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CVE-2025-39967

Full vulnerability record from the local CVENow database.

Description

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: 1. CALC_FONTSZ(h, pitch, charcount) performs h * pith * charcount multiplication with user-controlled values that can overflow. 2. FONT_EXTRA_WORDS * sizeof(int) + size addition can also overflow 3. 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.

Severity
HIGH
CVSS score
7.8 (v3.1)
Vulnerability status
Modified
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2025-10-15 08:15:34.210000
Last modified
2026-10-19 21:10:00.160000
View original CVE JSON 
{
  "id": "CVE-2025-39967",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2025-10-15T08:15:34.210",
  "lastModified": "2026-10-19T21:10:00.160",
  "vulnStatus": "Modified",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nfbcon: fix integer overflow in fbcon_do_set_font\n\nFix integer overflow vulnerabilities in fbcon_do_set_font() where font\nsize calculations could overflow when handling user-controlled font\nparameters.\n\nThe vulnerabilities occur when:\n1. CALC_FONTSZ(h, pitch, charcount) performs h * pith * charcount\n   multiplication with user-controlled values that can overflow.\n2. FONT_EXTRA_WORDS * sizeof(int) + size addition can also overflow\n3. This results in smaller allocations than expected, leading to buffer\n   overflows during font data copying.\n\nAdd explicit overflow checking using check_mul_overflow() and\ncheck_add_overflow() kernel helpers to safety validate all size\ncalculations before allocation."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nfbcon: corrige desbordamiento de entero en fbcon_do_set_font\n\nCorrige vulnerabilidades de desbordamiento de entero en fbcon_do_set_font() donde los cálculos del tamaño de la fuente podrían desbordarse al manejar parámetros de fuente controlados por el usuario.\n\nLas vulnerabilidades ocurren cuando:\n1. CALC_FONTSZ(h, pitch, charcount) realiza la multiplicación h * pith * charcount con valores controlados por el usuario que pueden desbordarse.\n2. La adición FONT_EXTRA_WORDS * sizeof(int) + size también puede desbordarse.\n3. Esto resulta en asignaciones más pequeñas de lo esperado, lo que lleva a desbordamientos de búfer durante la copia de datos de la fuente.\n\nAgrega verificación explícita de desbordamiento utilizando las funciones auxiliares del kernel check_mul_overflow() y check_add_overflow() para validar de forma segura todos los cálculos de tamaño antes de la asignación."
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