FKIE_CVE-2026-3904

Vulnerability from fkie_nvd - Published: 2026-03-11 14:16 - Updated: 2026-03-12 21:08
Severity ?
6.2 (Medium) - CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Summary
Calling NSS-backed functions that support caching via nscd may call the nscd client side code and in the GNU C Library version 2.36 under high load on x86_64 systems, the client may call memcmp on inputs that are concurrently modified by other processes or threads and crash. The nscd client in the GNU C Library uses the memcmp function with inputs that may be concurrently modified by another thread, potentially resulting in spurious cache misses, which in itself is not a security issue.  However in the GNU C Library version 2.36 an optimized implementation of memcmp was introduced for x86_64 which could crash when invoked with such undefined behaviour, turning this into a potential crash of the nscd client and the application that uses it. This implementation was backported to the 2.35 branch, making the nscd client in that branch vulnerable as well.  Subsequently, the fix for this issue was backported to all vulnerable branches in the GNU C Library repository. It is advised that distributions that may have cherry-picked the memcpy SSE2 optimization in their copy of the GNU C Library, also apply the fix to avoid the potential crash in the nscd client.
References
3ff69d7a-14f2-4f67-a097-88dee7810d18https://sourceware.org/bugzilla/show_bug.cgi?id=29863
3ff69d7a-14f2-4f67-a097-88dee7810d18https://sourceware.org/git/?p=glibc.git;a=blob_plain;f=advisories/GLIBC-SA-2026-0004;hb=HEAD
3ff69d7a-14f2-4f67-a097-88dee7810d18https://sourceware.org/git/?p=glibc.git;a=commit;h=8804157ad9da39631703b92315460808eac86b0c
3ff69d7a-14f2-4f67-a097-88dee7810d18https://sourceware.org/git/?p=glibc.git;a=commit;h=b712be52645282c706a5faa038242504feb06db5
af854a3a-2127-422b-91ae-364da2661108http://www.openwall.com/lists/oss-security/2026/03/11/5
Impacted products
Vendor Product Version
To clipboard 

{
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Calling NSS-backed functions that support caching via nscd may call the \nnscd client side code and in the GNU C Library version 2.36 under high \nload on x86_64 systems, the client may call memcmp on inputs that are \nconcurrently modified by other processes or threads and crash.\n\n\n\n\nThe nscd client in the GNU C Library uses the memcmp function with \ninputs that may be concurrently modified by another thread, potentially \nresulting in spurious cache misses, which in itself is not a security \nissue.\u00a0 However in the GNU C Library version 2.36 an optimized \nimplementation of memcmp was introduced for x86_64 which could crash \nwhen invoked with such undefined behaviour, turning this into a \npotential crash of the nscd client and the application that uses it. \nThis implementation was backported to the 2.35 branch, making the nscd \nclient in that branch vulnerable as well.\u00a0 Subsequently, the fix for \nthis issue was backported to all vulnerable branches in the GNU C \nLibrary repository.\n\n\nIt is advised that distributions that may have cherry-picked the memcpy \nSSE2 optimization in their copy of the GNU C Library, also apply the fix \nto avoid the potential crash in the nscd client."
    },
    {
      "lang": "es",
      "value": "Llamar a funciones respaldadas por NSS que soportan el almacenamiento en cach\u00e9 a trav\u00e9s de nscd puede llamar al c\u00f3digo del lado del cliente de nscd y en la biblioteca GNU C versi\u00f3n 2.36 bajo alta carga en sistemas x86_64, el cliente puede llamar a memcmp en entradas que son modificadas concurrentemente por otros procesos o hilos y colapsar.\n\nEl cliente nscd en la biblioteca GNU C utiliza la funci\u00f3n memcmp con entradas que pueden ser modificadas concurrentemente por otro hilo, lo que puede resultar en fallos de cach\u00e9 espurios, lo cual en s\u00ed mismo no es un problema de seguridad. Sin embargo, en la biblioteca GNU C versi\u00f3n 2.36 se introdujo una implementaci\u00f3n optimizada de memcmp para x86_64 que podr\u00eda colapsar cuando se invoca con dicho comportamiento indefinido, convirtiendo esto en un posible colapso del cliente nscd y de la aplicaci\u00f3n que lo utiliza. Esta implementaci\u00f3n fue retroportada a la rama 2.35, haciendo que el cliente nscd en esa rama tambi\u00e9n sea vulnerable. Posteriormente, la correcci\u00f3n para este problema fue retroportada a todas las ramas vulnerables en el repositorio de la biblioteca GNU C.\n\nSe aconseja que las distribuciones que puedan haber seleccionado la optimizaci\u00f3n memcpy SSE2 en su copia de la biblioteca GNU C, tambi\u00e9n apliquen la correcci\u00f3n para evitar el posible colapso en el cliente nscd."
    }
  ],
  "id": "CVE-2026-3904",
  "lastModified": "2026-03-12T21:08:22.643",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "LOCAL",
          "availabilityImpact": "HIGH",
          "baseScore": 6.2,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "NONE",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
          "version": "3.1"
        },
        "exploitabilityScore": 2.5,
        "impactScore": 3.6,
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "type": "Secondary"
      }
    ]
  },
  "published": "2026-03-11T14:16:30.113",
  "references": [
    {
      "source": "3ff69d7a-14f2-4f67-a097-88dee7810d18",
      "url": "https://sourceware.org/bugzilla/show_bug.cgi?id=29863"
    },
    {
      "source": "3ff69d7a-14f2-4f67-a097-88dee7810d18",
      "url": "https://sourceware.org/git/?p=glibc.git;a=blob_plain;f=advisories/GLIBC-SA-2026-0004;hb=HEAD"
    },
    {
      "source": "3ff69d7a-14f2-4f67-a097-88dee7810d18",
      "url": "https://sourceware.org/git/?p=glibc.git;a=commit;h=8804157ad9da39631703b92315460808eac86b0c"
    },
    {
      "source": "3ff69d7a-14f2-4f67-a097-88dee7810d18",
      "url": "https://sourceware.org/git/?p=glibc.git;a=commit;h=b712be52645282c706a5faa038242504feb06db5"
    },
    {
      "source": "af854a3a-2127-422b-91ae-364da2661108",
      "url": "http://www.openwall.com/lists/oss-security/2026/03/11/5"
    }
  ],
  "sourceIdentifier": "3ff69d7a-14f2-4f67-a097-88dee7810d18",
  "vulnStatus": "Awaiting Analysis",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-366"
        }
      ],
      "source": "3ff69d7a-14f2-4f67-a097-88dee7810d18",
      "type": "Secondary"
    }
  ]
}


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  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



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