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CVE-2025-39715

Full vulnerability record from the local CVENow database.

Description

In the Linux kernel, the following vulnerability has been resolved: parisc: Revise gateway LWS calls to probe user read access We use load and stbys,e instructions to trigger memory reference interruptions without writing to memory. Because of the way read access support is implemented, read access interruptions are only triggered at privilege levels 2 and 3. The kernel and gateway page execute at privilege level 0, so this code never triggers a read access interruption. Thus, it is currently possible for user code to execute a LWS compare and swap operation at an address that is read protected at privilege level 3 (PRIV_USER). Fix this by probing read access rights at privilege level 3 and branching to lws_fault if access isn't allowed.

Severity
MEDIUM
CVSS score
5.5 (v3.1)
Vulnerability status
Modified
Source identifier
416baaa9-dc9f-4396-8d5f-8c081fb06d67
Published
2025-09-05 18:15:48.990000
Last modified
2026-10-19 21:10:00.160000
View original CVE JSON 
{
  "id": "CVE-2025-39715",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
  "published": "2025-09-05T18:15:48.990",
  "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\nparisc: Revise gateway LWS calls to probe user read access\n\nWe use load and stbys,e instructions to trigger memory reference\ninterruptions without writing to memory. Because of the way read\naccess support is implemented, read access interruptions are only\ntriggered at privilege levels 2 and 3. The kernel and gateway\npage execute at privilege level 0, so this code never triggers\na read access interruption. Thus, it is currently possible for\nuser code to execute a LWS compare and swap operation at an\naddress that is read protected at privilege level 3 (PRIV_USER).\n\nFix this by probing read access rights at privilege level 3 and\nbranching to lws_fault if access isn't allowed."
    },
    {
      "lang": "es",
      "value": "En el kernel de Linux, la siguiente vulnerabilidad ha sido resuelta:\n\nparisc: Revisar las llamadas LWS de puerta de enlace para sondear el acceso de lectura del usuario\n\nUtilizamos las instrucciones load y stbys,e para activar interrupciones de referencia de memoria sin escribir en la memoria. Debido a la forma en que se implementa el soporte de acceso de lectura, las interrupciones de acceso de lectura solo se activan en los niveles de privilegio 2 y 3. El kernel y la página de puerta de enlace se ejecutan en el nivel de privilegio 0, por lo tanto, este código nunca activa una interrupción de acceso de lectura. Así, actualmente es posible que el código de usuario ejecute una operación LWS de comparación e intercambio en una dirección que está protegida contra lectura en el nivel de privilegio 3 (PRIV_USER).\n\nEsto se soluciona sondeando los derechos de acceso de lectura en el nivel de privilegio 3 y bifurcando a lws_fault si el acceso no está permitido."
    }
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          "product": "SIMATIC CN 4100",
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          "baseSeverity": "MEDIUM",
          "attackVector": "LOCAL",
          "attackComplexity": "LOW",
          "privilegesRequired": "LOW",
          "userInteraction": "NONE",
          "scope": "UNCHANGED",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "availabilityImpact": "HIGH"
        },
        "exploitabilityScore": 1.8,
        "impactScore": 3.6
      }
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  },
  "weaknesses": [
    {
      "source": "[email protected]",
      "type": "Primary",
      "description": [
        {
          "lang": "en",
          "value": "NVD-CWE-noinfo"
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