---
cve: "CVE-2026-48859"
severity: "MEDIUM"
cvss: 6.3
epss: "35%"
vendor: "erlang"
kev: false
exploited: false
published: "2026-06-10 16:17:12"
tags: [cve, security, medium]
source: tsecurity.de CVE-Dossier
exported: "2026-09-11T01:38:16+02:00"
---

# CVE-2026-48859

> 6.3 MEDIUM · 🧪 PoC

## Beschreibung

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.

## CVSS-Vektor

```
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
```

| Metrik | Wert | Bewertung |
|---|---|---|
| AV Angriffsvektor | Netzwerk | bad |
| AC Komplexität | Gering | bad |
| PR Privilegien | Keine | bad |
| UI Interaktion | Keine | bad |

## Patch verfügbar (OSV)

- 36b336d7675edfb976768465c5067bc8bc16ee9a (Commit)
- c342092ef4b369bb409d5b71ac8fd83bab74aedf (Commit)

## Referenzen

- <https://github.com/erlang/otp/security/advisories/GHSA-3w6p-vwhf-wvp4>
- <https://cna.erlef.org/cves/CVE-2026-48859.html>
- <https://osv.dev/vulnerability/EEF-CVE-2026-48859>
- <https://www.erlang.org/doc/system/versions.html#order-of-versions>
- <https://github.com/erlang/otp/commit/c342092ef4b369bb409d5b71ac8fd83bab74aedf>

---
_Exportiert aus dem [tsecurity.de CVE-Dossier](https://tsecurity.de/cve?cve=CVE-2026-48859) · Datenquellen: EUVD (ENISA), NVD, OSV, CISA KEV, FIRST EPSS, Exploit-DB, BSI BITS_