CVE-2026-48859
Low
No strong exploitation signal.
CVSS breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
| Attack Vector | N | Network |
| Attack Complexity | L | Low |
| Privileges Required | N | None |
| User Interaction | N | None |
| Scope | U | Unchanged |
| Confidentiality | L | Low |
| Integrity | N | None |
| Availability | N | None |
Timeline
- 2026-06-10 — Published (NVD)
- 2026-09-08 — Last modified (NVD)
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. 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 OTP 29.0.2, corresponding to ssh from 6.0 before 6.0.1.
Affected
References
- https://cna.erlef.org/cves/CVE-2026-48859.html
- https://github.com/erlang/otp/commit/c342092ef4b369bb409d5b71ac8fd83bab74aedf
- https://github.com/erlang/otp/security/advisories/GHSA-3w6p-vwhf-wvp4
- https://osv.dev/vulnerability/EEF-CVE-2026-48859
- https://www.erlang.org/doc/system/versions.html#order-of-versions