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NVD / CVE Program· CNA mitre

CVE-2018-15473: OpenSSH through 7.7 is prone to a user enumeration vulnerability due to not delaying bailout for an invalid authenticating user until after…

MediumCVSS 5.3 · v3.1—Weaponized Fix available

Noroxi assessment

Priority: This week (action score 60/100)

  • A ready-made attack module is public (Metasploit, Nuclei); exploiting it takes no special expertise.
  • A ready-made attack tool exists and the flaw can be exploited over the network without an account, so priority is at least “This week”.
  • Probability of exploitation in the next 30 days: 98.6% (FIRST EPSS); higher than 99.9% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: openssh (Alpine:v3.10) 7.7_p1-r4; openssh (Alpine:v3.5) 7.4_p1-r2; openssh (Alpine:v3.6) 7.5_p1-r3.

Don’t wait for the next maintenance window. Upgrade to openssh (Alpine:v3.10) 7.7_p1-r4; openssh (Alpine:v3.5) 7.4_p1-r2; openssh (Alpine:v3.6) 7.5_p1-r3 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

Published
Aug 17, 2018
Updated
Jun 16, 2026
EPSS
98.6% · 99th percentile

Report tools

JSON

Action score

60

This week

Don’t wait for the next maintenance window.

CVSS
21 / 40 · 5.3 / 10
CISA KEV
0 / 30 · Not listed
EPSS
30 / 30 · 98.6%
Ready-made attack tool
9 / 60 · floor: at least 60

CISA SSVC decision

Exploitation
proof of concept
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • Weaponized exploit exists
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
openbsdopenssh
debiandebian linux
redhatenterprise linux desktop
redhatenterprise linux server
redhatenterprise linux workstation
canonicalubuntu linux
netappcn1610 firmware
netappcn1610
netappaff baseboard management controller
netappcloud backup
netappdata ontap edge
netappfas baseboard management controller

and 12 more

Is OpenSSH on your server exposed to the internet?

The free port scanner finds the open ports on your server and matches the service versions it can read against known vulnerabilities. No account needed.

Run a port scan

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • canonical ubuntu linux14.04
  • canonical ubuntu linux16.04
  • canonical ubuntu linux18.04
  • debian debian linux8.0
  • debian debian linux9.0
  • netapp aff baseboard management controllerall versions
  • netapp cloud backupall versions
  • netapp clustered data ontapall versions
+12 more rows
  • netapp cn1610 firmwareall versions
  • netapp data ontapall versions
  • netapp data ontap edgeall versions
  • netapp fas baseboard management controllerall versions
  • netapp oncommand unified manager9.4 and later
  • netapp ontap select deployall versions
  • netapp service processorall versions
  • netapp steelstore cloud integrated storageall versions
  • netapp storage replication adapter7.2 and later
  • netapp vasa provider7.2 and later
  • netapp virtual storage console7.2 and later
  • openbsd opensshup to 7.7 inclusive

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Alpine:v3.10opensshbefore 7.7_p1-r47.7_p1-r4
Alpine:v3.5opensshbefore 7.4_p1-r27.4_p1-r2
Alpine:v3.6opensshbefore 7.5_p1-r37.5_p1-r3
Alpine:v3.7opensshbefore 7.5_p1-r97.5_p1-r9
Alpine:v3.8opensshbefore 7.7_p1-r37.7_p1-r3
Debian:12opensshbefore 1:7.7p1-41:7.7p1-4
Debian:8opensshbefore 1:6.7p1-5+deb8u51:6.7p1-5+deb8u5
Debian:9opensshbefore 1:7.4p1-10+deb9u41:7.4p1-10+deb9u4
openSUSE:Leap 15.2ssh-auditbefore 2.5.0-lp152.2.3.12.5.0-lp152.2.3.1
openSUSE:Leap 15.3ssh-auditbefore 2.5.0-bp153.2.3.12.5.0-bp153.2.3.1
openSUSE:Tumbleweedssh-auditbefore 2.5.0-1.22.5.0-1.2
Red Hat:enterprise_linux:6::clientopensshbefore 0:5.3p1-124.el6_100:5.3p1-124.el6_10
Red Hat:enterprise_linux:6::clientopenssh-askpassbefore 0:5.3p1-124.el6_100:5.3p1-124.el6_10
Red Hat:enterprise_linux:6::clientopenssh-clientsbefore 0:5.3p1-124.el6_100:5.3p1-124.el6_10
Red Hat:enterprise_linux:6::clientopenssh-debuginfobefore 0:5.3p1-124.el6_100:5.3p1-124.el6_10
Red Hat:enterprise_linux:6::clientopenssh-ldapbefore 0:5.3p1-124.el6_100:5.3p1-124.el6_10
Red Hat:enterprise_linux:6::clientopenssh-serverbefore 0:5.3p1-124.el6_100:5.3p1-124.el6_10
Red Hat:enterprise_linux:6::clientpam_ssh_agent_authbefore 0:0.9.3-124.el6_100:0.9.3-124.el6_10
Red Hat:enterprise_linux:7::clientopensshbefore 0:7.4p1-21.el70:7.4p1-21.el7
Red Hat:enterprise_linux:7::clientopenssh-askpassbefore 0:7.4p1-21.el70:7.4p1-21.el7
Red Hat:enterprise_linux:7::clientopenssh-cavsbefore 0:7.4p1-21.el70:7.4p1-21.el7
Red Hat:enterprise_linux:7::clientopenssh-clientsbefore 0:7.4p1-21.el70:7.4p1-21.el7
Red Hat:enterprise_linux:7::clientopenssh-debuginfobefore 0:7.4p1-21.el70:7.4p1-21.el7
Red Hat:enterprise_linux:7::clientopenssh-keycatbefore 0:7.4p1-21.el70:7.4p1-21.el7

+16

Same product

openbsd: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-123158sshd in OpenSSH before 10.6p2 on Linux, when musl libc is used without PAM, lacks a workaround for a password authentication bypass…KEV
    68This week
  • CVE-2023-38408The PKCS#11 feature in ssh-agent in OpenSSH before 9.3p2 has an insufficiently trustworthy search path, leading to remote code execution if…
    63This week
  • CVE-2016-6210sshd in OpenSSH before 7.3, when SHA256 or SHA512 are used for user password hashing, uses BLOWFISH hashing on a static password when the…
    60This week

Published before and after this one in the same product

  • ← EarlierCVE-2017-15906Oct 25, 2017 · The process_open function in sftp-server.c in OpenSSH before 7.6 does not properly prevent write operations in readonly mode, which allows…
    22Monitor
  • ← EarlierCVE-2016-10708Jan 21, 2018 · sshd in OpenSSH before 7.4 allows remote attackers to cause a denial of service (NULL pointer dereference and daemon crash) via an…
    35Monitor
  • Later →CVE-2018-15919Aug 28, 2018 · Remotely observable behaviour in auth-gss2.c in OpenSSH through 7.8 could be used by remote attackers to detect existence of users on a…
    22Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
alpine:openssh7.7_p1-r4 · Alpine:v3.10Package registry (OSV)
debian:openssh1:7.7p1-4 · Debian:12Package registry (OSV)
opensuse:ssh-audit2.5.0-bp153.2.3.1 · openSUSE:Leap 15.3Package registry (OSV)
opensuse:ssh-audit2.5.0-lp152.2.3.1 · openSUSE:Leap 15.2Package registry (OSV)
red hat:openssh0:5.3p1-124.el6_10 · Red Hat:enterprise_linux:6::clientPackage registry (OSV)
red hat:openssh-askpass0:5.3p1-124.el6_10 · Red Hat:enterprise_linux:6::clientPackage registry (OSV)
red hat:openssh-cavs0:7.4p1-21.el7 · Red Hat:enterprise_linux:7::clientPackage registry (OSV)
red hat:openssh-clients0:5.3p1-124.el6_10 · Red Hat:enterprise_linux:6::clientPackage registry (OSV)
red hat:openssh-debuginfo0:5.3p1-124.el6_10 · Red Hat:enterprise_linux:6::clientPackage registry (OSV)
red hat:openssh-keycat0:7.4p1-21.el7 · Red Hat:enterprise_linux:7::clientPackage registry (OSV)
red hat:openssh-ldap0:5.3p1-124.el6_10 · Red Hat:enterprise_linux:6::clientPackage registry (OSV)
red hat:openssh-server0:5.3p1-124.el6_10 · Red Hat:enterprise_linux:6::clientPackage registry (OSV)
red hat:openssh-server-sysvinit0:7.4p1-21.el7 · Red Hat:enterprise_linux:7::clientPackage registry (OSV)
red hat:pam_ssh_agent_auth0:0.9.3-124.el6_10 · Red Hat:enterprise_linux:6::clientPackage registry (OSV)
suse:openssh6.2p2-0.41.5.1 · SUSE:Linux Enterprise Point of Sale 11 SP3Package registry (OSV)
suse:openssh-askpass-gnome6.2p2-0.41.5.1 · SUSE:Linux Enterprise Point of Sale 11 SP3Package registry (OSV)
suse:openssh-openssl16.6p1-19.6.1 · SUSE:Linux Enterprise Server 11-SECURITYPackage registry (OSV)
suse:ssh-audit2.5.0-bp153.2.3.1 · SUSE:Package Hub 15 SP3Package registry (OSV)

Exploit status

Weaponized

A ready exploit tool or active in-the-wild use is known for this vulnerability. This should be your top priority.

Evidence

  • Metasploit module ×1
  • Exploit-DB entry ×3
  • Nuclei detection template ×2
  • Proof-of-concept repository on GitHub ×41

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Proof-of-concept repository on GitHub41 repositories2018-08-17 → 2026-10-08
Exploit-DB entryremote2018-08-21
Exploit-DB entryremote2018-08-16
Exploit-DB entryremote2018-12-04
Metasploit moduleauxiliary/scanner/ssh/ssh_enumusersSSH Username Enumerationauxiliary—
Nuclei detection templateNuclei template mikrotik-ssh-detect —
Nuclei detection templateNuclei template openssh-detect —

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. First PoC-2 d
  2. Published
  3. TodayNov 14, 2026+3010 d

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Not on record for this CVE: EPSS history · researcher credit · variant or chain candidate · public bounty program.

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
low · data can be read
Integrity
none
Availability
none
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
Low
Integrity impact
None
Availability impact
None

Weakness class (CWE)

CWE-362 · Concurrent Execution using Shared Resource with Improper Synchronization ('Race Condition')

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

References

Show all references (14 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records