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CVE-2026-0819

Status: AnalyzedLow (2.2)—

A stack buffer overflow vulnerability exists in wolfSSL's PKCS7 SignedData encoding functionality. In wc_PKCS7_BuildSignedAttributes(), when adding custom signed attributes, the code passes an incorrect capacity value (esd->signedAttribsCount) to EncodeAttributes() instead of the remaining available space in the fixed-size signedAttribs[7] array. When an application sets pkcs7->signedAttribsSz to a value greater than MAX_SIGNED_ATTRIBS_SZ (default 7) minus the number of default attributes already added, EncodeAttributes() writes beyond the array bounds, causing stack memory corruption.

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In WOLFSSL_SMALL_STACK builds, this becomes heap corruption. Exploitation requires an application that allows untrusted input to control the signedAttribs array size when calling wc_PKCS7_EncodeSignedData() or related signing functions.

CVSS

Exploitation probability (EPSS)

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

Affected technologies (1)

Wolfssl — Wolfssl

CWEs

References

Raw JSON (NVD)

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{
  "id": "CVE-2026-0819",
  "cveTags": [],
  "metrics": {
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          "options": [
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              "technicalImpact": "total"
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          "version": "2.0.3",
          "timestamp": "2026-03-19T17:19:26.928139Z"
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          "valueDensity": "NOT_DEFINED",
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          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED"
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          "vendor": "wolfSSL",
          "modules": [
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          "programRoutines": [
            {
              "name": "wc_PKCS7_EncodeSignedData()"
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  "published": "2026-03-19T17:16:21.657",
  "references": [
    {
      "url": "https://github.com/wolfSSL/wolfssl/pull/9630",
      "tags": [
        "Issue Tracking",
        "Patch"
      ],
      "source": "facts@wolfssl.com"
    }
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  "vulnStatus": "Analyzed",
  "weaknesses": [
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      "type": "Secondary",
      "source": "facts@wolfssl.com",
      "description": [
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          "value": "CWE-121"
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        {
          "lang": "en",
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      "value": "A stack buffer overflow vulnerability exists in wolfSSL's PKCS7 SignedData encoding functionality. In wc_PKCS7_BuildSignedAttributes(), when adding custom signed attributes, the code passes an incorrect capacity value (esd->signedAttribsCount) to EncodeAttributes() instead of the remaining available space in the fixed-size signedAttribs[7] array. When an application sets pkcs7->signedAttribsSz to a value greater than MAX_SIGNED_ATTRIBS_SZ (default 7) minus the number of default attributes already added, EncodeAttributes() writes beyond the array bounds, causing stack memory corruption. In WOLFSSL_SMALL_STACK builds, this becomes heap corruption. Exploitation requires an application that allows untrusted input to control the signedAttribs array size when calling wc_PKCS7_EncodeSignedData() or related signing functions."
    },
    {
      "lang": "es",
      "value": "Una vulnerabilidad de desbordamiento de búfer de pila existe en la funcionalidad de codificación de datos firmados (SignedData) PKCS7 de wolfSSL. En wc_PKCS7_BuildSignedAttributes(), al añadir atributos firmados personalizados, el código pasa un valor de capacidad incorrecto (esd->signedAttribsCount) a EncodeAttributes() en lugar del espacio disponible restante en el array de tamaño fijo signedAttribs[7]. Cuando una aplicación establece pkcs7->signedAttribsSz a un valor mayor que MAX_SIGNED_ATTRIBS_SZ (por defecto 7) menos el número de atributos por defecto ya añadidos, EncodeAttributes() escribe más allá de los límites del array, causando corrupción de memoria de pila. En compilaciones WOLFSSL_SMALL_STACK, esto se convierte en corrupción de heap. La explotación requiere una aplicación que permita que la entrada no confiable controle el tamaño del array signedAttribs al llamar a wc_PKCS7_EncodeSignedData() o funciones de firma relacionadas."
    }
  ],
  "lastModified": "2026-06-17T10:11:26.320",
  "configurations": [
    {
      "nodes": [
        {
          "negate": false,
          "cpeMatch": [
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}