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CVE-2025-39713

Full vulnerability record from the local CVENow database.

Description

In the Linux kernel, the following vulnerability has been resolved: media: rainshadow-cec: fix TOCTOU race condition in rain_interrupt() In the interrupt handler rain_interrupt(), the buffer full check on rain->buf_len is performed before acquiring rain->buf_lock. This creates a Time-of-Check to Time-of-Use (TOCTOU) race condition, as rain->buf_len is concurrently accessed and modified in the work handler rain_irq_work_handler() under the same lock. Multiple interrupt invocations can race, with each reading buf_len before it becomes full and then proceeding. This can lead to both interrupts attempting to write to the buffer, incrementing buf_len beyond its capacity (DATA_SIZE) and causing a buffer overflow. Fix this bug by moving the spin_lock() to before the buffer full check. This ensures that the check and the subsequent buffer modification are performed atomically, preventing the race condition. An corresponding spin_unlock() is added to the overflow path to correctly release the lock. This possible bug was found by an experimental static analysis tool developed by our team.

Severity
MEDIUM
CVSS score
4.7 (v3.1)
Vulnerability status
Modified
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2025-09-05 18:15:48.720000
Last modified
2026-10-19 21:10:00.160000
View original CVE JSON 
{
  "id": "CVE-2025-39713",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2025-09-05T18:15:48.720",
  "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\nmedia: rainshadow-cec: fix TOCTOU race condition in rain_interrupt()\n\nIn the interrupt handler rain_interrupt(), the buffer full check on\nrain->buf_len is performed before acquiring rain->buf_lock. This\ncreates a Time-of-Check to Time-of-Use (TOCTOU) race condition, as\nrain->buf_len is concurrently accessed and modified in the work\nhandler rain_irq_work_handler() under the same lock.\n\nMultiple interrupt invocations can race, with each reading buf_len\nbefore it becomes full and then proceeding. This can lead to both\ninterrupts attempting to write to the buffer, incrementing buf_len\nbeyond its capacity (DATA_SIZE) and causing a buffer overflow.\n\nFix this bug by moving the spin_lock() to before the buffer full\ncheck. This ensures that the check and the subsequent buffer modification\nare performed atomically, preventing the race condition. An corresponding\nspin_unlock() is added to the overflow path to correctly release the\nlock.\n\nThis possible bug was found by an experimental static analysis tool\ndeveloped by our team."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nmedia: rainshadow-cec: corrección de una condición de carrera TOCTOU en rain_interrupt()\n\nEn el gestor de interrupciones rain_interrupt(), la comprobación de búfer lleno en rain->buf_len se realiza antes de adquirir rain->buf_lock. Esto crea una condición de carrera de Tiempo de Comprobación a Tiempo de Uso (TOCTOU), ya que rain->buf_len es accedido y modificado concurrentemente en el gestor de trabajo rain_irq_work_handler() bajo el mismo bloqueo.\n\nMúltiples invocaciones de interrupción pueden competir, con cada una leyendo buf_len antes de que se llene y luego procediendo. Esto puede llevar a que ambas interrupciones intenten escribir en el búfer, incrementando buf_len más allá de su capacidad (DATA_SIZE) y causando un desbordamiento de búfer.\n\nSe corrige este error moviendo el spin_lock() a antes de la comprobación de búfer lleno. Esto asegura que la comprobación y la modificación posterior del búfer se realicen atómicamente, previniendo la condición de carrera. Se añade un spin_unlock() correspondiente a la ruta de desbordamiento para liberar correctamente el bloqueo.\n\nEste posible error fue encontrado por una herramienta experimental de análisis estático desarrollada por nuestro equipo."
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          "vendor": "Siemens",
          "product": "SIMATIC CN 4100",
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          "baseSeverity": "MEDIUM",
          "attackVector": "LOCAL",
          "attackComplexity": "HIGH",
          "privilegesRequired": "LOW",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
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  "weaknesses": [
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      "source": "[email protected]",
      "type": "Primary",
      "description": [
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          "value": "CWE-367"
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