{"id":"CVE-2026-48859","summary":"SSH server timing side-channel in ssh_auth:check_password/3 allows unauthenticated username enumeration","details":"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.","aliases":["EEF-CVE-2026-48859","GHSA-3w6p-vwhf-wvp4"],"modified":"2026-07-08T08:13:37.386442460Z","published":"2026-06-10T14:35:43.553Z","database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/48xxx/CVE-2026-48859.json","cna_assigner":"EEF","cwe_ids":["CWE-208"],"unresolved_ranges":[{"source":"AFFECTED_FIELD","extracted_events":[{"introduced":"6.0"},{"fixed":"6.0.1"},{"introduced":"032d1bc9491a3975c68faf9bc7776115d6ae3005"},{"fixed":"c342092ef4b369bb409d5b71ac8fd83bab74aedf"}]}]},"references":[{"type":"WEB","url":"https://cna.erlef.org/cves/CVE-2026-48859.html"},{"type":"WEB","url":"https://github.com"},{"type":"WEB","url":"https://osv.dev/vulnerability/EEF-CVE-2026-48859"},{"type":"WEB","url":"https://www.erlang.org/doc/system/versions.html#order-of-versions"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/48xxx/CVE-2026-48859.json"},{"type":"ADVISORY","url":"https://github.com/erlang/otp/security/advisories/GHSA-3w6p-vwhf-wvp4"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-48859"},{"type":"FIX","url":"https://github.com/erlang/otp/commit/c342092ef4b369bb409d5b71ac8fd83bab74aedf"},{"type":"PACKAGE","url":"https://github.com/erlang/otp"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/erlang/otp","events":[{"introduced":"550d7b7898706c7822362c42e7b93120c1d1f29a"},{"fixed":"36b336d7675edfb976768465c5067bc8bc16ee9a"},{"fixed":"c342092ef4b369bb409d5b71ac8fd83bab74aedf"}],"database_specific":{"source":["CPE_RANGE","REFERENCES"],"extracted_events":[{"introduced":"29.0"},{"fixed":"29.0.2"}],"cpe":"cpe:2.3:a:erlang:erlang\\/otp:*:*:*:*:*:*:*:*"}}],"versions":["OTP-29.0.1","OTP-29.0"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-48859.json"}}],"schema_version":"1.7.5","severity":[{"type":"CVSS_V4","score":"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"}]}