OpenSSH through 7.7 is prone to a user enumeration vulnerability due to not delaying bailout for an invalid authenticating user until after
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% · 100th percentile
- CWE
- CWE-362
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Report tools
Action score
51
Plan
Add it to your regular patch cycle.
- CVSS
- 21 / 40 · 5.3 / 10
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 30 / 30 · 98.6%
CISA SSVC decision
- Exploitation
- proof of concept
- Automatable
- no
- Technical impact
- partial
Vulnrichment: CISA's decision-tree inputs.
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| openbsd | openssh | cpe:2.3:a:openbsd:openssh |
| debian | debian linux | cpe:2.3:o:debian:debian_linux |
| redhat | enterprise linux desktop | cpe:2.3:o:redhat:enterprise_linux_desktop |
| redhat | enterprise linux server | cpe:2.3:o:redhat:enterprise_linux_server |
| redhat | enterprise linux workstation | cpe:2.3:o:redhat:enterprise_linux_workstation |
| canonical | ubuntu linux | cpe:2.3:o:canonical:ubuntu_linux |
| netapp | cn1610 firmware | cpe:2.3:o:netapp:cn1610_firmware |
| netapp | cn1610 | cpe:2.3:h:netapp:cn1610 |
| netapp | aff baseboard management controller | cpe:2.3:a:netapp:aff_baseboard_management_controller |
| netapp | cloud backup | cpe:2.3:a:netapp:cloud_backup |
| netapp | data ontap edge | cpe:2.3:a:netapp:data_ontap_edge |
| netapp | fas baseboard management controller | cpe:2.3:a:netapp:fas_baseboard_management_controller |
and 12 more
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
- 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.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Alpine:v3.10 | openssh | before 7.7_p1-r4 | 7.7_p1-r4 |
| Alpine:v3.5 | openssh | before 7.4_p1-r2 | 7.4_p1-r2 |
| Alpine:v3.6 | openssh | before 7.5_p1-r3 | 7.5_p1-r3 |
| Alpine:v3.7 | openssh | before 7.5_p1-r9 | 7.5_p1-r9 |
| Alpine:v3.8 | openssh | before 7.7_p1-r3 | 7.7_p1-r3 |
| Debian:12 | openssh | before 1:7.7p1-4 | 1:7.7p1-4 |
| Debian:8 | openssh | before 1:6.7p1-5+deb8u5 | 1:6.7p1-5+deb8u5 |
| Debian:9 | openssh | before 1:7.4p1-10+deb9u4 | 1:7.4p1-10+deb9u4 |
| openSUSE:Leap 15.2 | ssh-audit | before 2.5.0-lp152.2.3.1 | 2.5.0-lp152.2.3.1 |
| openSUSE:Tumbleweed | ssh-audit | before 2.5.0-1.2 | 2.5.0-1.2 |
| Red Hat:enterprise_linux:6::client | openssh | before 0:5.3p1-124.el6_10 | 0:5.3p1-124.el6_10 |
| Red Hat:enterprise_linux:6::client | openssh-askpass | before 0:5.3p1-124.el6_10 | 0:5.3p1-124.el6_10 |
| Red Hat:enterprise_linux:6::client | openssh-clients | before 0:5.3p1-124.el6_10 | 0:5.3p1-124.el6_10 |
| Red Hat:enterprise_linux:6::client | openssh-debuginfo | before 0:5.3p1-124.el6_10 | 0:5.3p1-124.el6_10 |
| Red Hat:enterprise_linux:6::client | openssh-ldap | before 0:5.3p1-124.el6_10 | 0:5.3p1-124.el6_10 |
| Red Hat:enterprise_linux:6::client | openssh-server | before 0:5.3p1-124.el6_10 | 0:5.3p1-124.el6_10 |
| Red Hat:enterprise_linux:6::client | pam_ssh_agent_auth | before 0:0.9.3-124.el6_10 | 0:0.9.3-124.el6_10 |
| Red Hat:enterprise_linux:7::client | openssh | before 0:7.4p1-21.el7 | 0:7.4p1-21.el7 |
| Red Hat:enterprise_linux:7::client | openssh-askpass | before 0:7.4p1-21.el7 | 0:7.4p1-21.el7 |
| Red Hat:enterprise_linux:7::client | openssh-cavs | before 0:7.4p1-21.el7 | 0:7.4p1-21.el7 |
| Red Hat:enterprise_linux:7::client | openssh-clients | before 0:7.4p1-21.el7 | 0:7.4p1-21.el7 |
| Red Hat:enterprise_linux:7::client | openssh-debuginfo | before 0:7.4p1-21.el7 | 0:7.4p1-21.el7 |
| Red Hat:enterprise_linux:7::client | openssh-keycat | before 0:7.4p1-21.el7 | 0:7.4p1-21.el7 |
| Red Hat:enterprise_linux:7::client | openssh-ldap | before 0:7.4p1-21.el7 | 0:7.4p1-21.el7 |
+16
Same product
openbsd: all recordsOther highest-scoring records for the same primary product.
- 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-2023-25136OpenSSH server (sshd) 9.1 introduced a double-free vulnerability during options.kex_algorithms handling.53Plan
- 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 us50Plan
- CVE-2016-6515The auth_password function in auth-passwd.c in sshd in OpenSSH before 7.3 does not limit password lengths for password authentication, which48Plan
- CVE-2002-0640Buffer overflow in sshd in OpenSSH 2.3.1 through 3.3 may allow remote attackers to execute arbitrary code via a large number of responses du48Plan
- CVE-2006-5051Signal handler race condition in OpenSSH before 4.4 allows remote attackers to cause a denial of service (crash), and possibly execute arbit45Plan
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| Alpine:openssh | 7.7_p1-r4 · Alpine:v3.10 | Package registry (OSV) |
| Debian:openssh | 1:7.7p1-4 · Debian:12 | Package registry (OSV) |
| openSUSE:ssh-audit | 2.5.0-lp152.2.3.1 · openSUSE:Leap 15.2 | Package registry (OSV) |
| Red Hat:openssh | 0:5.3p1-124.el6_10 · Red Hat:enterprise_linux:6::client | Package registry (OSV) |
| Red Hat:openssh-askpass | 0:5.3p1-124.el6_10 · Red Hat:enterprise_linux:6::client | Package registry (OSV) |
| Red Hat:openssh-cavs | 0:7.4p1-21.el7 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| Red Hat:openssh-clients | 0:5.3p1-124.el6_10 · Red Hat:enterprise_linux:6::client | Package registry (OSV) |
| Red Hat:openssh-debuginfo | 0:5.3p1-124.el6_10 · Red Hat:enterprise_linux:6::client | Package registry (OSV) |
| Red Hat:openssh-keycat | 0:7.4p1-21.el7 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| Red Hat:openssh-ldap | 0:5.3p1-124.el6_10 · Red Hat:enterprise_linux:6::client | Package registry (OSV) |
| Red Hat:openssh-server | 0:5.3p1-124.el6_10 · Red Hat:enterprise_linux:6::client | Package registry (OSV) |
| Red Hat:openssh-server-sysvinit | 0:7.4p1-21.el7 · Red Hat:enterprise_linux:7::client | Package registry (OSV) |
| Red Hat:pam_ssh_agent_auth | 0:0.9.3-124.el6_10 · Red Hat:enterprise_linux:6::client | Package registry (OSV) |
| SUSE:openssh | 6.2p2-0.41.5.1 · SUSE:Linux Enterprise Point of Sale 11 SP3 | Package registry (OSV) |
| SUSE:openssh-askpass-gnome | 6.2p2-0.41.5.1 · SUSE:Linux Enterprise Point of Sale 11 SP3 | Package registry (OSV) |
| SUSE:openssh-openssl1 | 6.6p1-19.6.1 · SUSE:Linux Enterprise Server 11-SECURITY | Package registry (OSV) |
| SUSE:ssh-audit | 2.5.0-bp153.2.3.1 · SUSE:Package Hub 15 SP3 | Package 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.
| Source | Kind | Date |
|---|---|---|
| Exploit-DB entry | remote | 2018-08-21 |
| Exploit-DB entry | remote | 2018-08-16 |
| Exploit-DB entry | remote | 2018-12-04 |
| Metasploit module | auxiliary/scanner/ssh/ssh_enumusersSSH Username Enumerationauxiliary | — |
| Nuclei detection template | Nuclei template mikrotik-ssh-detect | — |
| Nuclei detection template | Nuclei template openssh-detect | — |
| Proof-of-concept repository on GitHub | stars:0 | 2020-11-26 |
| Proof-of-concept repository on GitHub | stars:159 | 2018-08-17 |
| Proof-of-concept repository on GitHub | stars:3 | 2018-08-19 |
| Proof-of-concept repository on GitHub | stars:534 | 2018-08-21 |
| Proof-of-concept repository on GitHub | stars:116 | 2018-10-03 |
| Proof-of-concept repository on GitHub | stars:0 | 2018-10-08 |
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.
- First PoC-2 d
- Published
- TodaySep 29, 2026+2965 d
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
No nightly-computed relations.
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
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.
Attack patterns (CAPEC)
ATT&CK techniques
—
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
- Fix✗ → ✓
For records you follow, these changes also arrive as notifications. →
References
- www.openwall.com/lists/oss-security/2018/08/15/5
- www.securityfocus.com/bid/105140
- www.securitytracker.com/id/1041487
- access.redhat.com/errata/RHSA-2019:0711
- access.redhat.com/errata/RHSA-2019:2143
- bugs.debian.org/906236
- cert-portal.siemens.com/productcert/pdf/ssa-412672.pdf
- github.com/openbsd/src/commit/779974d35b4859c07bc3cb8a12c74b43b0a7d1e0
- lists.debian.org/debian-lts-announce/2018/08/msg00022.html
- psirt.global.sonicwall.com/vuln-detail/SNWLID-2018-0011
- security.gentoo.org/glsa/201810-03
- security.netapp.com/advisory/ntap-20181101-0001/
- usn.ubuntu.com/3809-1/
- www.debian.org/security/2018/dsa-4280
- www.oracle.com/security-alerts/cpujan2020.html
Vendor advisories and official records. Exploit/PoC links are deliberately left out.