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CVE-2026-53422

Full vulnerability record from the local CVENow database.

Description

Observable Response Discrepancy vulnerability in Erlang OTP ssh (ssh_sftpd module) allows an authenticated SFTP user to enumerate the existence of files and directories outside the configured root directory. The SSH_FXP_REALPATH handler in ssh_sftpd calls relate_file_name/3 with Canonicalize=false, unlike every other SFTP operation handler. This allows .. components in the requested path to bypass the is_within_root/2 check without being resolved. The un-canonicalized path then enters resolve_symlinks/2, which walks up the directory tree above the configured root and issues read_link() syscalls on arbitrary filesystem paths. An authenticated SFTP client can exploit this by sending a REALPATH request with a crafted traversal path. The server response differs depending on whether the target path exists on the host filesystem (SSH_FXP_NAME when the path resolves successfully, SSH_FX_NO_SUCH_FILE when it does not). This creates a path-existence oracle that an attacker can use to enumerate the filesystem structure outside the configured root, including the existence of sensitive files, directories, and mount points. The vulnerability leaks only the existence of paths. No file contents, credentials, or write access are obtainable through this issue alone. The information gained may assist further attacks when combined with other vulnerabilities. This vulnerability is associated with program files lib/ssh/src/ssh_sftpd.erl and program routine ssh_sftpd:handle_op/4. This issue affects OTP from OTP 17.0 before OTP 29.0.3, OTP 28.5.0.3 and OTP 27.3.4.14, corresponding to ssh from 3.0.1 before 6.0.2, 5.5.2.2 and 5.2.11.9.

Severity
LOW
CVSS score
2.3 (v4.0)
Vulnerability status
Modified
Source identifier
6b3ad84c-e1a6-4bf7-a703-f496b71e49db
Published
2026-07-02 17:17:01.473000
Last modified
2026-10-25 21:10:00.770000
View original CVE JSON 
{
  "id": "CVE-2026-53422",
  "sourceIdentifier": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
  "published": "2026-07-02T17:17:01.473",
  "lastModified": "2026-10-25T21:10:00.770",
  "vulnStatus": "Modified",
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Observable Response Discrepancy vulnerability in Erlang OTP ssh (ssh_sftpd module) allows an authenticated SFTP user to enumerate the existence of files and directories outside the configured root directory.\n\nThe SSH_FXP_REALPATH handler in ssh_sftpd calls relate_file_name/3 with Canonicalize=false, unlike every other SFTP operation handler. This allows .. components in the requested path to bypass the is_within_root/2 check without being resolved. The un-canonicalized path then enters resolve_symlinks/2, which walks up the directory tree above the configured root and issues read_link() syscalls on arbitrary filesystem paths.\n\nAn authenticated SFTP client can exploit this by sending a REALPATH request with a crafted traversal path. The server response differs depending on whether the target path exists on the host filesystem (SSH_FXP_NAME when the path resolves successfully, SSH_FX_NO_SUCH_FILE when it does not). This creates a path-existence oracle that an attacker can use to enumerate the filesystem structure outside the configured root, including the existence of sensitive files, directories, and mount points.\n\nThe vulnerability leaks only the existence of paths. No file contents, credentials, or write access are obtainable through this issue alone. The information gained may assist further attacks when combined with other vulnerabilities.\n\nThis vulnerability is associated with program files lib/ssh/src/ssh_sftpd.erl and program routine ssh_sftpd:handle_op/4.\n\nThis issue affects OTP from OTP 17.0 before OTP 29.0.3, OTP 28.5.0.3 and OTP 27.3.4.14, corresponding to ssh from 3.0.1 before 6.0.2, 5.5.2.2 and 5.2.11.9."
    },
    {
      "lang": "es",
      "value": "Vulnerabilidad de Discrepancia de Respuesta Observable en Erlang OTP ssh (módulo ssh_sftpd) permite a un usuario SFTP autenticado enumerar la existencia de archivos y directorios fuera del directorio raíz configurado.\n\nEl gestor SSH_FXP_REALPATH en ssh_sftpd llama a relate_file_name/3 con Canonicalize=false, a diferencia de cualquier otro gestor de operación SFTP. Esto permite que los componentes ’..’ en la ruta solicitada eludan la verificación is_within_root/2 sin ser resueltos. La ruta no canonizada luego entra en resolve_symlinks/2, que asciende por el árbol de directorios por encima de la raíz configurada y emite llamadas al sistema read_link() en rutas de sistema de archivos arbitrarias.\n\nUn cliente SFTP autenticado puede explotar esto enviando una solicitud REALPATH con una ruta de recorrido manipulada. La respuesta del servidor difiere dependiendo de si la ruta objetivo existe en el sistema de archivos del host (SSH_FXP_NAME cuando la ruta se resuelve con éxito, SSH_FX_NO_SUCH_FILE cuando no lo hace). Esto crea un oráculo de existencia de rutas que un atacante puede usar para enumerar la estructura del sistema de archivos fuera de la raíz configurada, incluyendo la existencia de archivos sensibles, directorios y puntos de montaje.\n\nLa vulnerabilidad solo filtra la existencia de rutas. No se pueden obtener contenidos de archivos, credenciales o acceso de escritura a través de este problema por sí solo. La información obtenida puede ayudar a futuros ataques cuando se combina con otras vulnerabilidades.\n\nEsta vulnerabilidad está asociada con los archivos de programa lib/ssh/src/ssh_sftpd.erl y la rutina de programa ssh_sftpd:handle_op/4.\n\nEste problema afecta a OTP desde OTP 17.0 hasta OTP 29.0.3, 28.5.0.3 y 27.3.4.14 correspondiente a ssh desde 3.0.1 hasta 6.0.2, 5.5.2.2 y 5.2.11.9."
    }
  ],
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          "product": "OTP",
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          "packageName": "ssh",
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            "cpe:2.3:a:erlang:erlang\\/otp:*:*:*:*:*:*:*:*"
          ],
          "modules": [
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          "programFiles": [
            "src/ssh_sftpd.erl"
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          "programRoutines": [
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              "name": "ssh_sftpd:handle_op/4"
            }
          ],
          "repo": "https://github.com/erlang/otp",
          "packageURL": "pkg:otp/ssh?repository_url=https:%2F%2Fgithub.com%2Ferlang%2Fotp&vcs_url=git%20https:%2F%2Fgithub.com%2Ferlang%2Fotp.git",
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              "lessThan": "*",
              "versionType": "otp",
              "status": "affected",
              "changes": [
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                {
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          "programRoutines": [
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          ],
          "repo": "https://github.com/erlang/otp",
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                  "at": "28.5.0.3",
                  "status": "unaffected"
                },
                {
                  "at": "27.3.4.14",
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                }
              ]
            },
            {
              "version": "84adefa331c4159d432d22840663c38f155cd4c1",
              "lessThan": "*",
              "versionType": "git",
              "status": "affected",
              "changes": [
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                  "status": "unaffected"
                },
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                  "status": "unaffected"
                },
                {
                  "at": "c5a8f50ae68888ff243c5c741a06d2b3a4b48b7a",
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        }
      ]
    }
  ],
  "metrics": {
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          "userInteraction": "NONE",
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          "vulnIntegrityImpact": "NONE",
          "vulnAvailabilityImpact": "NONE",
          "subConfidentialityImpact": "NONE",
          "subIntegrityImpact": "NONE",
          "subAvailabilityImpact": "NONE",
          "exploitMaturity": "NOT_DEFINED",
          "confidentialityRequirement": "NOT_DEFINED",
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          "availabilityRequirement": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
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          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "valueDensity": "NOT_DEFINED",
          "vulnerabilityResponseEffort": "NOT_DEFINED",
          "providerUrgency": "NOT_DEFINED"
        }
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    ],
    "cvssMetricV31": [
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        "source": "[email protected]",
        "type": "Primary",
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    "ssvcV203": [
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          "id": "CVE-2026-53422",
          "options": [
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              "exploitation": "none"
            },
            {
              "automatable": "no"
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            {
              "technicalImpact": "partial"
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          "role": "CISA Coordinator",
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      "description": [
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          "lang": "en",
          "value": "CWE-204"
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  "configurations": [
    {
      "nodes": [
        {
          "operator": "OR",
          "negate": false,
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      "url": "https://cna.erlef.org/cves/CVE-2026-53422.html",
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