HOMEVULNERABILITIESCVE-2018-15599
MEDIUM

CVE-2018-15599

CWE-200Published: August 21, 2018· Updated: Jun 17, 2026

5.3
CVSS v3.1

Official Description

The recv_msg_userauth_request function in svr-auth.c in Dropbear through 2018.76 is prone to a user enumeration vulnerability because username validity affects how fields in SSH_MSG_USERAUTH messages are handled, a similar issue to CVE-2018-15473 in an unrelated codebase.

NVD Source

Technical Analysis

CVE-2018-15599 can be exploited remotely over the network without requiring physical or adjacent access, significantly expanding the attack surface for threat actors.

The vulnerability requires no privileges and no user interaction, making it a prime target for automated exploitation campaigns and worm-like propagation.

From a weakness classification perspective (CWE-200): Information exposure vulnerabilities leak sensitive data to unauthorized actors.

CVSS v3.1 Vector Breakdown

Exploitability
Attack VectorNetwork
Attack ComplexityLow
Privileges Req.None
User InteractionNone
ScopeUnchanged
Impact
ConfidentialityLow
IntegrityNone
AvailabilityNone
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

Affected Vendors & Products

Debian1 product(s)
debian linux
dropbear_ssh_project1 product(s)
dropbear ssh
Source: NVD CPE · 2 total CPE entries

Exploit & PoC Resources

NO KNOWN EXPLOITNo public exploit confirmed at this time
Exploit-DB
Offensive Security exploit database
GitHub PoC Search
Community PoC repositories
Rapid7 / Metasploit
Metasploit module search
PacketStorm
Security advisories & exploits
NVD Detail
Official NIST entry
MITRE CVE
CVE Program entry
External links open in a new tab. Always verify in a controlled environment before use.

Official Patches & Advisories

ADVISORYhttp://lists.ucc.gu.uwa.edu.au/pipermail/dropbear/2018q3/002108.html
ADVISORYhttp://lists.ucc.gu.uwa.edu.au/pipermail/dropbear/2018q3/002109.html
ADVISORYhttps://lists.debian.org/debian-lts-announce/2018/08/msg00026.html
ADVISORYhttps://old.reddit.com/r/blackhat/comments/97ywnm/openssh_username_enumeration/e4e05n2/
ADVISORYhttp://lists.ucc.gu.uwa.edu.au/pipermail/dropbear/2018q3/002108.html
ADVISORYhttp://lists.ucc.gu.uwa.edu.au/pipermail/dropbear/2018q3/002109.html
ADVISORYhttps://lists.debian.org/debian-lts-announce/2018/08/msg00026.html
ADVISORYhttps://old.reddit.com/r/blackhat/comments/97ywnm/openssh_username_enumeration/e4e05n2/

All References (10)

→
http://lists.ucc.gu.uwa.edu.au/pipermail/dropbear/2018q3/002108.htmlMailing List · Third Party Advisory
→
http://lists.ucc.gu.uwa.edu.au/pipermail/dropbear/2018q3/002109.htmlMailing List · Third Party Advisory
→
https://lists.debian.org/debian-lts-announce/2018/08/msg00026.htmlMailing List · Third Party Advisory
→
https://matt.ucc.asn.au/dropbear/CHANGES
→
https://old.reddit.com/r/blackhat/comments/97ywnm/openssh_username_enumeration/e4e05n2/Third Party Advisory
→
http://lists.ucc.gu.uwa.edu.au/pipermail/dropbear/2018q3/002108.htmlMailing List · Third Party Advisory
→
http://lists.ucc.gu.uwa.edu.au/pipermail/dropbear/2018q3/002109.htmlMailing List · Third Party Advisory
→
https://lists.debian.org/debian-lts-announce/2018/08/msg00026.htmlMailing List · Third Party Advisory
→
https://matt.ucc.asn.au/dropbear/CHANGES
→
https://old.reddit.com/r/blackhat/comments/97ywnm/openssh_username_enumeration/e4e05n2/Third Party Advisory

Quick Facts

CVE IDCVE-2018-15599
CVSS Score5.3 / 10
SeverityMEDIUM
WeaknessCWE-200
CISA KEVNo
Affected2 vendor(s)
PublishedAug 21, 2018

Related CVEs (CWE-200)

CVE-2025-53624
10.0
CVE-2008-1155
10.0
CVE-2025-29270
10.0
CVE-2026-40965
10.0
CVE-2008-1252
10.0
CVE-2011-0376
10.0

Recommended Actions

  • →Apply vendor patches immediately
  • →Monitor CVE-2018-15599 in threat intel feeds
  • →Review IDS/IPS signatures for exploitation attempts
Data sourced from NVD (NIST), CISA KEV, and EPSS (FIRST). Analysis generated by CTIWatch. CVE data is provided under the NVD usage policy.
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