CVE-2018-15919

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 target system when GSS2 is in use. NOTE: the discoverer states 'We understand that the OpenSSH developers do not want to treat such a username enumeration (or "oracle") as a vulnerability.'

Published: 2018-08-28 Last update: 2025-12-18 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2018-15919 is rated Moderate Risk (51.4/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 2.07%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2018-15919

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-03-04 1.21% 2.07% +0.87%
2 2026-03-01 2.07% 1.21% -0.87%
3 2026-02-04 — 2.07% —

Full EPSS history (48 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2018-15919

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 1.4 134c704f-9b21-4f2e-91b3-4a467353bcc0
5.3 3.0 MEDIUM
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 3.9 1.4 [email protected]
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:P/I:N/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:N)
No availability impact.
 10.0 2.9 [email protected]

Weakness enumeration for CVE-2018-15919

OS Trackers for CVE-2018-15919

vendor priority summary link
alpine — CVE-2018-15919: 1 source package rows (openssh); 15 state rows across 5 repos (3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-main); fixed 0, open 15. https://security.alpinelinux.org/vuln/CVE-2018-15919
debian unimportant CVE-2018-15919 unimportant priority: Debian including 1 source packages (openssh), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): open 5. https://security-tracker.debian.org/tracker/CVE-2018-15919
redhat medium — https://access.redhat.com/security/cve/CVE-2018-15919
suse medium — https://www.suse.com/security/cve/CVE-2018-15919/
ubuntu low CVE-2018-15919 low priority: Ubuntu including 2 source packages (openssh, openssh-ssh1), 16 status rows across 8 suites (bionic, cosmic, disco, eoan, focal, trusty, upstream, xenial): ignored 13, DNE 2, needs-triage 1. https://ubuntu.com/security/CVE-2018-15919

Affected software / configurations for CVE-2018-15919

Vendor Product Version Raw CPE
openbsd openssh >= 5.9, <= 7.8 cpe:2.3:a:openbsd:openssh:*:*:*:*:*:*:*:*
netapp cloud_backup — cpe:2.3:a:netapp:cloud_backup:-:*:*:*:*:*:*:*
netapp data_ontap_edge — cpe:2.3:a:netapp:data_ontap_edge:-:*:*:*:*:*:*:*
netapp ontap_select_deploy — cpe:2.3:a:netapp:ontap_select_deploy:-:*:*:*:*:*:*:*
netapp steelstore — cpe:2.3:a:netapp:steelstore:-:*:*:*:*:*:*:*
netapp cn1610_firmware — cpe:2.3:o:netapp:cn1610_firmware:-:*:*:*:*:*:*:*

References for CVE-2018-15919

URL Tags
http://seclists.org/oss-sec/2018/q3/180 Mailing List Patch Third Party Advisory
http://www.securityfocus.com/bid/105163 Third Party Advisory VDB Entry
https://security.netapp.com/advisory/ntap-20181221-0001/ Third Party Advisory
cvelogic Threat Intelligence