Vulnerability in Erlang Erlang\/otp
CVE-2026-48859
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.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N.
EPSS exploit prediction
EPSS: 0.006 (47.7th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 48th percentile — 47.7% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.004 · newest: 0.006 · change: +0.003
Affected products
- Erlang Erlang\/otp
- Erlang Erlang\/ssh
- Erlang Otp — versions 6.0, 29.0, 032d1bc9491a3975c68faf9bc7776115d6ae3005
Weakness classification (CWE)
References
- 6b3ad84c-e1a6-4bf7-a703-f496b71e49db (related, Third Party Advisory, Mitigation)
- 6b3ad84c-e1a6-4bf7-a703-f496b71e49db (Patch, patch)
- 6b3ad84c-e1a6-4bf7-a703-f496b71e49db (related, vendor-advisory, Mitigation, Vendor Advisory)
- 6b3ad84c-e1a6-4bf7-a703-f496b71e49db (related, Third Party Advisory, Mitigation)
- 6b3ad84c-e1a6-4bf7-a703-f496b71e49db (Product, x_version-scheme)
Frequently asked questions
- What is CVE-2026-48859?
- CVE-2026-48859 is a medium-severity vulnerability in Erlang Erlang\/otp, classified under CWE-208. CVSS score: 5.3/10. Published 2026-06-10.
- How severe is CVE-2026-48859?
- Medium severity. CVSS v3 base score is 5.3 out of 10.