CVE-2018-15473

MEDIUMNVD 5.39.0▲
EchelonGraph scoreMEDIUM confidence

Score elevated to 9.0 because EPSS predicts 99% probability of exploitation within the next 30 days (top 0.1% of all CVEs). NVD baseline CVSS 5.3 retained for reference. Confidence: see factors.

Triggered by: EPSS exploit prediction ≥85%
Sources: epss, ghsa, nvd
Trending — 3 sources updated this weekWeaponized
5.3
EchelonGraph verdictPatch this weekExploitation is likely or a public exploit exists.
  • 3,664 internet-exposed hosts are running an affected version right now
  • High exploitation likelihood — EPSS 99%
CISA-KEV: Not listedEPSS: 99%CVSS: 5.3Exploit: NoneExposed: 3,664

A fix is available — apply it.

OpenSSH through 7.7 is prone to a user enumeration vulnerability due to not delaying bailout for an invalid authenticating user until after the packet containing the request has been fully parsed, related to auth2-gss.c, auth2-hostbased.c, and auth2-pubkey.c.

Live · internet exposure

3,664 internet-exposed hosts are running an affected version of CVE-2018-15473 right now.

across 49 countries (China, United States, Germany, Singapore, Japan)top: openssh
See the live KEV-Exposure radar →Found passively from public internet-scan data — aggregate, host-redacted.

EchelonGraph is the only CVE feed that fuses live vulnerability intelligence with its own live internet-exposure radar — so you see not just that a CVE is exploited, but how much of the internet is exposed to it right now.

CVSS v3
5.3
EG Score
9.0(medium)
EG Risk
80(Track)
EG Risk 80/100SSVC: Track

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity90% × 45%
Exploitation99% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS
99.9%
KEV
Not listed

Published

August 17, 2018

Last Modified

December 17, 2025

References (36)

Patch Availability(3)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntussh-krb5 (1:7.2p2-4ubuntu2.6) @ xenial2026-05-28ubuntu
redhatopenssh-0:7.4p1-21.el72019-08-06redhat
redhatopenssh-0:5.3p1-124.el6_102019-04-09redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

All Vendor Advisories

(3)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 5× in last 7d / 8× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-23 14:15 UTCEPSS rescore
  2. 2026-07-23 14:15 UTCEPSS rescore
  3. 2026-07-23 01:33 UTCEG score recompute
  4. 2026-07-22 22:13 UTCEG score recompute
  5. 2026-07-21 06:48 UTCOSV refresh
  6. 2026-07-09 19:06 UTCEPSS rescore
  7. 2026-07-05 02:27 UTCEPSS rescore
  8. 2026-07-04 02:26 UTCOSV refresh
  9. 2026-06-15 17:45 UTCEPSS rescore
  10. 2026-06-15 14:13 UTCOSV refresh
  11. 2026-06-13 22:58 UTCEPSS rescore
  12. 2026-06-13 22:58 UTCEPSS rescore
  13. 2026-06-11 13:57 UTCEPSS rescore
  14. 2026-06-10 13:19 UTCEPSS rescore
  15. 2026-06-07 15:22 UTCEPSS rescore
  16. 2026-06-07 15:22 UTCEPSS rescore
  17. 2026-06-05 22:45 UTCEPSS rescore
  18. 2026-06-05 22:44 UTCEPSS rescore
  19. 2026-05-31 00:14 UTCEPSS rescore
  20. 2026-05-31 00:14 UTCEPSS rescore
  21. 2026-05-29 13:41 UTCEPSS rescore
  22. 2026-05-28 03:58 UTCEG score recompute
  23. 2026-05-28 03:58 UTCVendor advisory
  24. 2026-05-28 03:58 UTCGHSA enrichment
  25. 2026-05-27 13:38 UTCEPSS rescore
Show 3 more
  1. 2026-05-27 13:38 UTCEPSS rescore
  2. 2026-05-26 13:42 UTCEPSS rescore
  3. 2026-05-26 13:42 UTCEPSS rescore

Publicly available exploits

(10 references)

Working exploit code is in the public domain (8 GitHub PoCs) (2 Exploit-DB entries). Defenders should treat patch urgency accordingly — public PoCs typically lead to mass-exploitation within 24-72 hours.

  • GitHub PoCK3rn3l-32/Threaded-CVE-2018-15473
    First seen Mar 25, 2026

    A Python 3 reimplementation of the classic CVE-2018-15473 OpenSSH user enumeration exploit, extended with multi-threading, wordlist support, automatic vulnerability detection, and thread-safe exploit patching.

    Open source ↗
  • GitHub PoCsergiovks/SSH-User-Enum-Python3-CVE-2018-15473
    First seen Mar 9, 2023

    SSH User Enumerator in Python3, CVE-2018-15473, I updated the code of this exploit (https://www.exploit-db.com/exploits/45939) to work with python3 instead of python2.

    Open source ↗
  • GitHub PoCMrDottt/CVE-2018-15473
    First seen Sep 14, 2021

    CVE-2018-15473 Exploit

    Open source ↗
  • GitHub PoCSait-Nuri/CVE-2018-15473
    First seen Nov 29, 2020

    OpenSSH 2.3 < 7.7 - Username Enumeration

    Open source ↗
  • Exploit-DBEDB-45939
    First seen Dec 4, 2018

    OpenSSH < 7.7 - User Enumeration (2)

    Open source ↗
  • GitHub PoCJoeBlackSecurity/SSHUsernameBruter-SSHUB
    First seen Oct 31, 2018

    Fully functional script for brute forcing SSH and trying credentials - CVE-2018-15473

    Open source ↗
  • GitHub PoCr3dxpl0it/CVE-2018-15473
    First seen Oct 24, 2018

    OpenSSH 7.7 - Username Enumeration

    Open source ↗
  • GitHub PoCepi052/cve-2018-15473
    First seen Oct 3, 2018

    Multi-threaded, IPv6 aware, wordlists/single-user username enumeration via CVE-2018-15473

    Open source ↗
  • Exploit-DBEDB-45233✓ verified
    First seen Aug 21, 2018

    OpenSSH 2.3 < 7.7 - Username Enumeration

    Open source ↗
  • GitHub PoCRhynorater/CVE-2018-15473-Exploit
    First seen Aug 21, 2018

    Exploit written in Python for CVE-2018-15473 with threading and export formats

    Open source ↗

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2018-15473?
CVE-2018-15473 is a medium vulnerability published on August 17, 2018. OpenSSH through 7.7 is prone to a user enumeration vulnerability due to not delaying bailout for an invalid authenticating user until after the packet containing the request has been fully parsed, related to auth2-gss.c, auth2-hostbased.c, and auth2-pubkey.c.
When was CVE-2018-15473 disclosed?
CVE-2018-15473 was first published in the National Vulnerability Database on August 17, 2018, with the most recent update on December 17, 2025. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2018-15473 actively exploited?
CVE-2018-15473 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 99.9% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2018-15473?
CVE-2018-15473 has a CVSS v3 base score of 5.3 (NVD). EchelonGraph synthesises NVD + CISA KEV + FIRST EPSS + GHSA into a combined EG score of 9.0.
How do I remediate CVE-2018-15473?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2018-15473, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2018-15473

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