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 the packet containing the request has been fully parsed, related to auth2-gss.c, auth2-hostbased.c, and auth2-pubkey.c.

CVSS: 5.3Medium
Exploited in the wild: Not knownPublic exploit code; not in CISA KEV
EPSS: 98.7%chance of exploitation in the next 30 daystop 0.1% of scored CVEsFIRST score of 11 Nov 2026
Fix: Patch availablesee the advisories in the references
Published: 17 Aug 2018analysed here 12 Nov 2026

Summary

Triage

Exploitable: At runtime
Attack vector: network
Weakness: CWE-362 Common Weakness
Can a WAF block it?: Partly. See why

The summary, impact and action text on this page are written by our AI analysis pipeline, or taken from the NVD description when a CVE was imported from NVD. They are not the vendor's wording: check them against the sources. A longer AI executive summary and technical analysis are generated for signed-in accounts on the Max plan.

Affected products

Products named in our analysis

openbsd:openssh
debian:debian_linux
redhat:enterprise_linux_desktop
redhat:enterprise_linux_server
redhat:enterprise_linux_workstation
canonical:ubuntu_linux
netapp:cn1610_firmware
netapp:aff_baseboard_management_controller
netapp:cloud_backup
netapp:data_ontap_edge
netapp:fas_baseboard_management_controller
netapp:oncommand_unified_manager
netapp:ontap_select_deploy
netapp:service_processor
netapp:steelstore_cloud_integrated_storage
netapp:virtual_storage_console
netapp:clustered_data_ontap
netapp:data_ontap
netapp:vasa_provider
netapp:storage_replication_adapter
oracle:sun_zfs_storage_appliance_kit
siemens:scalance_x204rna_firmware

Fix and mitigation

WAF and other mitigations

Can a WAF block it? Partly. The bug can be reached over the network, so generic WAF rules may stop some attacks. Its weakness type is unknown, so we cannot be more precise.

Also consider: patch

Based on the weakness type only; no CVE-specific evidence yet. We check Cloudflare, AWS, Google Cloud Armor and Azure; for Akamai, Imperva, Fastly, F5, ask your vendor.

Remediation steps (AI-written)

Step-by-step remediation is generated for accounts on the Max plan, for CVEs that match a technology in their stack. Add this technology to your stack to see the fix checklist.

Exploitation evidence

CISA KEV catalog: Not listed as of our last sync.
Public exploit code: Yes: 3 on Exploit-DB · 1 Metasploit module · 41 GitHub proofs of concept

and 37 more repositories

Listed so you can judge urgency, not as a recommendation to run anything. GitHub “proofs of concept” are unvetted: some are fake or carry malware. Exploit-DB marks the entries its staff verified.

Timeline

16 Aug 2018First public exploit or proof of concept
17 Aug 2018Published2 days later
12 Nov 2026Analysed by vulneraibility.com3,009 days (about 8 years) later

CVSS vector

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

Metric	Value	What it means
Attack vector	NetworkReachable over the internet or any routable network.	Reachable over the internet or any routable network.
Attack complexity	LowRepeatable attack, no special conditions.	Repeatable attack, no special conditions.
Privileges required	NoneThe attacker needs no prior access.	The attacker needs no prior access.
User interaction	NoneNo victim action needed.	No victim action needed.
Scope	UnchangedImpact stays within the vulnerable component.	Impact stays within the vulnerable component.
Confidentiality	LowPartial data disclosure.	Partial data disclosure.
Integrity	NoneNo unauthorised modification.	No unauthorised modification.
Availability	NoneThe service stays up.	The service stays up.

Common questions

Is CVE-2018-15473 being exploited?

Not confirmed. CVE-2018-15473 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 99% probability of exploitation in the next 30 days.

How severe is CVE-2018-15473?

CVE-2018-15473 is rated Medium with a CVSS score of 5.3. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.

Is there a patch for CVE-2018-15473?

Yes. A fix has been recorded for CVE-2018-15473. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.

What does CVE-2018-15473 affect?

CVE-2018-15473 affects openbsd:openssh, debian:debian_linux, redhat:enterprise_linux_desktop, redhat:enterprise_linux_server, and 18 further products or versions. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.

Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.

References

NVD CVE.org CVE Details Source

Where the data on this page comes from

CVE List (CVE.org): description, affected versions, references; CVE Terms of Use
NVD: CVSS and CPE data
FIRST EPSS: exploit probability and percentile
Exploit-DB: published exploits
Metasploit Framework: exploit and scanner modules
PoC-in-GitHub: GitHub repositories that claim a proof of concept

Summary, impact and triage tags: written by our AI analysis pipeline from the sources above. Check them against the sources.

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