SSH server timing side-channel in ssh_auth:check_password/3 allows unauthenticated username enumeration_CVE-2026-48859

{
    "lastseen": "",
    "description": "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.",
    "published": "2026-06-10T14:35:43.553Z",
    "modified": "2026-06-10T16:19:43.145Z",
    "type": "cve",
    "title": "SSH server timing side-channel in ssh_auth:check_password/3 allows unauthenticated username enumeration",
    "source": "EEF",
    "references": "https://github.com/erlang/otp/security/advisories/GHSA-3w6p-vwhf-wvp4\nhttps://cna.erlef.org/cves/CVE-2026-48859.html\nhttps://osv.dev/vulnerability/EEF-CVE-2026-48859\nhttps://www.erlang.org/doc/system/versions.html#order-of-versions\nhttps://github.com/erlang/otp/commit/c342092ef4b369bb409d5b71ac8fd83bab74aedf",
    "id": "CVE-2026-48859",
    "bulletinFamily": "",
    "cwe": [
        "CWE-208"
    ],
    "cvelist": null,
    "sourceData": "Erlang OTP 6.0\nErlang OTP 29.0\nErlang OTP 032d1bc9491a3975c68faf9bc7776115d6ae3005",
    "sourceHref": "",
    "cvss": {
        "score": 6.3,
        "severity": "MEDIUM",
        "vector": "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",
        "version": "4.0"
    },
    "cvss2": [],
    "cvss3": {
        "version": "",
        "vectorString": "",
        "baseScore": 0,
        "baseSeverity": "",
        "attackVector": "",
        "attackComplexity": "",
        "privilegesRequired": "",
        "userInteraction": "",
        "scope": "",
        "confidentialityImpact": "",
        "integrityImpact": "",
        "availabilityImpact": "",
        "cvssV3": {
            "version": "",
            "vectorString": "",
            "baseScore": 0,
            "baseSeverity": "",
            "attackVector": "",
            "attackComplexity": "",
            "privilegesRequired": "",
            "userInteraction": "",
            "scope": "",
            "confidentialityImpact": "",
            "integrityImpact": "",
            "availabilityImpact": ""
        }
    },
    "href": "",
    "category_name": "CVE",
    "post_link": "",
    "product": "OTP",
    "version": "6.0",
    "vendor": "Erlang",
    "ai_description": "",
    "ai_severity": "",
    "ai_vendor": "",
    "ai_product": "",
    "ai_version": "",
    "ai_score": 0
}