FKIE_CVE-2026-48859

Vulnerability from fkie_nvd - Published: 2026-06-10 16:17 - Updated: 2026-06-17 10:55
Severity
5.3 (Medium) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Summary
Observable Timing Discrepancy vulnerability in Erlang/OTP ssh (ssh_auth, ssh_options modules) allows unauthenticated remote username enumeration via timing side-channel in password authentication. When the SSH daemon is configured with the user_passwords or password option, ssh_auth:check_password/3 performs a PBKDF2-SHA256 computation with 600,000 iterations (~300ms) for valid usernames, but returns immediately (~0ms) for invalid usernames via the ssh_options:get_password_option/2 path. This timing difference is detectable in a single authentication attempt and allows an unauthenticated attacker to distinguish valid from invalid usernames. The user_passwords and password options are documented as intended for test purposes; the recommended alternative is pwdfun, which is not affected by this vulnerability. This vulnerability is associated with program files lib/ssh/src/ssh_auth.erl and lib/ssh/src/ssh_options.erl. This issue affects OTP from OTP 29.0 before 29.0.2 corresponding to ssh from 6.0 before 6.0.1.
References
6b3ad84c-e1a6-4bf7-a703-f496b71e49dbhttps://cna.erlef.org/cves/CVE-2026-48859.htmlMitigation, Third Party Advisory
6b3ad84c-e1a6-4bf7-a703-f496b71e49dbhttps://github.com/erlang/otp/commit/c342092ef4b369bb409d5b71ac8fd83bab74aedfPatch
6b3ad84c-e1a6-4bf7-a703-f496b71e49dbhttps://github.com/erlang/otp/security/advisories/GHSA-3w6p-vwhf-wvp4Mitigation, Vendor Advisory
6b3ad84c-e1a6-4bf7-a703-f496b71e49dbhttps://osv.dev/vulnerability/EEF-CVE-2026-48859Mitigation, Third Party Advisory
6b3ad84c-e1a6-4bf7-a703-f496b71e49dbhttps://www.erlang.org/doc/system/versions.html#order-of-versionsProduct
Impacted products
Vendor Product Version
erlang erlang\/otp *
erlang erlang\/ssh *
To clipboard 

{
  "affected": [
    {
      "affectedData": [
        {
          "cpes": [
            "cpe:2.3:a:erlang:erlang\\/otp:*:*:*:*:*:*:*:*"
          ],
          "defaultStatus": "unknown",
          "modules": [
            "ssh_auth",
            "ssh_options"
          ],
          "packageName": "ssh",
          "packageURL": "pkg:otp/ssh?repository_url=https:%2F%2Fgithub.com%2Ferlang%2Fotp\u0026vcs_url=git%20https:%2F%2Fgithub.com%2Ferlang%2Fotp.git",
          "product": "OTP",
          "programFiles": [
            "src/ssh_auth.erl",
            "src/ssh_options.erl"
          ],
          "programRoutines": [
            {
              "name": "ssh_auth:check_password/3"
            },
            {
              "name": "ssh_options:get_password_option/2"
            }
          ],
          "repo": "https://github.com/erlang/otp",
          "vendor": "Erlang",
          "versions": [
            {
              "lessThan": "6.0.1",
              "status": "affected",
              "version": "6.0",
              "versionType": "otp"
            }
          ]
        },
        {
          "collectionURL": "https://github.com",
          "cpes": [
            "cpe:2.3:a:erlang:erlang\\/otp:*:*:*:*:*:*:*:*"
          ],
          "defaultStatus": "unknown",
          "modules": [
            "ssh_auth",
            "ssh_options"
          ],
          "packageName": "erlang/otp",
          "packageURL": "pkg:github/erlang/otp",
          "product": "OTP",
          "programFiles": [
            "lib/ssh/src/ssh_auth.erl",
            "lib/ssh/src/ssh_options.erl"
          ],
          "programRoutines": [
            {
              "name": "ssh_auth:check_password/3"
            },
            {
              "name": "ssh_options:get_password_option/2"
            }
          ],
          "repo": "https://github.com/erlang/otp",
          "vendor": "Erlang",
          "versions": [
            {
              "lessThan": "29.0.2",
              "status": "affected",
              "version": "29.0",
              "versionType": "otp"
            },
            {
              "lessThan": "c342092ef4b369bb409d5b71ac8fd83bab74aedf",
              "status": "affected",
              "version": "032d1bc9491a3975c68faf9bc7776115d6ae3005",
              "versionType": "git"
            }
          ]
        }
      ],
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db"
    }
  ],
  "configurations": [
    {
      "nodes": [
        {
          "cpeMatch": [
            {
              "criteria": "cpe:2.3:a:erlang:erlang\\/otp:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "F4AB1573-4E81-4338-B65A-B3C94C7249FA",
              "versionEndExcluding": "29.0.2",
              "versionStartIncluding": "29.0",
              "vulnerable": true
            },
            {
              "criteria": "cpe:2.3:a:erlang:erlang\\/ssh:*:*:*:*:*:*:*:*",
              "matchCriteriaId": "0BF9A1F8-83F5-4BEB-A972-3AF5B15947EF",
              "versionEndExcluding": "6.0.1",
              "versionStartIncluding": "6.0",
              "vulnerable": true
            }
          ],
          "negate": false,
          "operator": "OR"
        }
      ]
    }
  ],
  "cveTags": [],
  "descriptions": [
    {
      "lang": "en",
      "value": "Observable Timing Discrepancy vulnerability in Erlang/OTP ssh (ssh_auth, ssh_options modules) allows unauthenticated remote username enumeration via timing side-channel in password authentication.\n\nWhen the SSH daemon is configured with the user_passwords or password option, ssh_auth:check_password/3 performs a PBKDF2-SHA256 computation with 600,000 iterations (~300ms) for valid usernames, but returns immediately (~0ms) for invalid usernames via the ssh_options:get_password_option/2 path. This timing difference is detectable in a single authentication attempt and allows an unauthenticated attacker to distinguish valid from invalid usernames.\n\nThe user_passwords and password options are documented as intended for test purposes; the recommended alternative is pwdfun, which is not affected by this vulnerability.\n\nThis vulnerability is associated with program files lib/ssh/src/ssh_auth.erl and lib/ssh/src/ssh_options.erl.\n\nThis issue affects OTP from OTP 29.0 before 29.0.2 corresponding to ssh from 6.0 before 6.0.1."
    }
  ],
  "id": "CVE-2026-48859",
  "lastModified": "2026-06-17T10:55:18.960",
  "metrics": {
    "cvssMetricV31": [
      {
        "cvssData": {
          "attackComplexity": "LOW",
          "attackVector": "NETWORK",
          "availabilityImpact": "NONE",
          "baseScore": 5.3,
          "baseSeverity": "MEDIUM",
          "confidentialityImpact": "LOW",
          "integrityImpact": "NONE",
          "privilegesRequired": "NONE",
          "scope": "UNCHANGED",
          "userInteraction": "NONE",
          "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N",
          "version": "3.1"
        },
        "exploitabilityScore": 3.9,
        "impactScore": 1.4,
        "source": "nvd@nist.gov",
        "type": "Primary"
      }
    ],
    "cvssMetricV40": [
      {
        "cvssData": {
          "Automatable": "NOT_DEFINED",
          "Recovery": "NOT_DEFINED",
          "Safety": "NOT_DEFINED",
          "attackComplexity": "LOW",
          "attackRequirements": "PRESENT",
          "attackVector": "NETWORK",
          "availabilityRequirement": "NOT_DEFINED",
          "baseScore": 6.3,
          "baseSeverity": "MEDIUM",
          "confidentialityRequirement": "NOT_DEFINED",
          "exploitMaturity": "NOT_DEFINED",
          "integrityRequirement": "NOT_DEFINED",
          "modifiedAttackComplexity": "NOT_DEFINED",
          "modifiedAttackRequirements": "NOT_DEFINED",
          "modifiedAttackVector": "NOT_DEFINED",
          "modifiedPrivilegesRequired": "NOT_DEFINED",
          "modifiedSubAvailabilityImpact": "NOT_DEFINED",
          "modifiedSubConfidentialityImpact": "NOT_DEFINED",
          "modifiedSubIntegrityImpact": "NOT_DEFINED",
          "modifiedUserInteraction": "NOT_DEFINED",
          "modifiedVulnAvailabilityImpact": "NOT_DEFINED",
          "modifiedVulnConfidentialityImpact": "NOT_DEFINED",
          "modifiedVulnIntegrityImpact": "NOT_DEFINED",
          "privilegesRequired": "NONE",
          "providerUrgency": "NOT_DEFINED",
          "subAvailabilityImpact": "NONE",
          "subConfidentialityImpact": "NONE",
          "subIntegrityImpact": "NONE",
          "userInteraction": "NONE",
          "valueDensity": "NOT_DEFINED",
          "vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
          "version": "4.0",
          "vulnAvailabilityImpact": "NONE",
          "vulnConfidentialityImpact": "LOW",
          "vulnIntegrityImpact": "NONE",
          "vulnerabilityResponseEffort": "NOT_DEFINED"
        },
        "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
        "type": "Secondary"
      }
    ],
    "ssvcV203": [
      {
        "source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
        "ssvcData": {
          "id": "CVE-2026-48859",
          "options": [
            {
              "exploitation": "none"
            },
            {
              "automatable": "yes"
            },
            {
              "technicalImpact": "partial"
            }
          ],
          "role": "CISA Coordinator",
          "timestamp": "2026-06-10T16:19:16.914933Z",
          "version": "2.0.3"
        }
      }
    ]
  },
  "published": "2026-06-10T16:17:12.373",
  "references": [
    {
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
      "tags": [
        "Mitigation",
        "Third Party Advisory"
      ],
      "url": "https://cna.erlef.org/cves/CVE-2026-48859.html"
    },
    {
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
      "tags": [
        "Patch"
      ],
      "url": "https://github.com/erlang/otp/commit/c342092ef4b369bb409d5b71ac8fd83bab74aedf"
    },
    {
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
      "tags": [
        "Mitigation",
        "Vendor Advisory"
      ],
      "url": "https://github.com/erlang/otp/security/advisories/GHSA-3w6p-vwhf-wvp4"
    },
    {
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
      "tags": [
        "Mitigation",
        "Third Party Advisory"
      ],
      "url": "https://osv.dev/vulnerability/EEF-CVE-2026-48859"
    },
    {
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
      "tags": [
        "Product"
      ],
      "url": "https://www.erlang.org/doc/system/versions.html#order-of-versions"
    }
  ],
  "sourceIdentifier": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
  "vulnStatus": "Analyzed",
  "weaknesses": [
    {
      "description": [
        {
          "lang": "en",
          "value": "CWE-208"
        }
      ],
      "source": "6b3ad84c-e1a6-4bf7-a703-f496b71e49db",
      "type": "Secondary"
    }
  ]
}


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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.