Predictive Vulnerability Intelligence.

Product

  • Product
  • Pricing
  • Documentation

Company

  • About
  • Partnerships
  • Blog
  • Support

Legal

  • Terms
  • Privacy
  • Data Licensing

© 2026 FAUCET Technologies LLC. All rights reserved.

CVE-2019-16905

26
FAUCET Score

CVE-2019-16905 is a pre-authentication integer overflow vulnerability affecting OpenSSH versions 7.7 through 7.9 and 8.x before 8.1, specifically when compiled with an experimental XMSS key type. This flaw, rated High (CVSS 7.8), allows for memory corruption and local code execution due to an error in the XMSS key parsing algorithm. While the potential impact is significant (confidentiality, integrity, and availability), the vulnerability requires a client or server to be configured with a crafted XMSS key, and the XMSS implementation is experimental and not officially supported in portable OpenSSH builds. There is no evidence of active exploitation, public exploit code, or significant community discussion surrounding this CVE.

Impacted Technologies

VendorProductVersion(s)CPE
>= 7.7, <= 7.9CPE matchmatch criteria
cpe:2.3:a:openbsd:openssh:*:*:*:*:*:*:*:*
>= 8.0, < 8.1CPE matchmatch criteria
cpe:2.3:a:openbsd:openssh:*:*:*:*:*:*:*:*
Range not provided by sourceCPE matchmatch criteria
cpe:2.3:a:netapp:cloud_backup:-:*:*:*:*:*:*:*
Range not provided by sourceCPE matchmatch criteria
cpe:2.3:a:netapp:steelstore_cloud_integrated_storage:-:*:*:*:*:*:*:*
< 3.2.7CPE matchmatch criteria
cpe:2.3:o:siemens:scalance_x204rna_firmware:*:*:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

7.8HIGH

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

Attack Vector
LOCAL
Attack Complexity
LOW
Privileges Required
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
1.8
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
2.17%
Probability of exploitation in next 30 days
EPSS Percentile
80.4%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0217 is in the 97th percentile among its peer group of 17,070 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.2 Bluesky, 0.1 Mastodon, and 0.2 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (4)

microsoftpatch availablevia msrc
Product: 17023-16820Fixed in: -
microsoftpatch availablevia msrc
Product: cm1 openssh 8.0p1-9 on CBL Mariner 1.0Fixed in: -
microsoftpatch availablevia msrc
Product: CBL Mariner 1.0 x64Fixed in: 8.0p1-9
microsoftpatch availablevia msrc
Product: CBL Mariner 1.0 ARMFixed in: 8.0p1-9

Vendor Advisories (3)

microsoft2020-Sep/CVE-2019-16905

CVE-2019-16905

Sep 8, 2020
microsoft2019-Oct/CVE-2019-16905Important

OpenSSH 7.7 through 7.9 and 8.x before 8.1 when compiled with an experimental key type has a pre-authentication integer overflow if a client or server is configured to use a crafted XMSS key. This leads to memory corruption and local code execution because of an error in the XMSS key parsing algorithm. NOTE: the XMSS implementation is considered experimental in all released OpenSSH versions and there is no supported way to enable it when building portable OpenSSH.

Oct 8, 2019
redhatCVE-2019-16905Important

openssh: an integer overflow in the private key parsing code for the XMSS key type

Aug 28, 2019

References

bugzilla.suse.com / show_bug.cgi
Issue TrackingThird Party Advisory
cert-portal.siemens.com / productcert/pdf/ssa-412672.pdf
Third Party Advisory
cvsweb.openbsd.org / cgi-bin/cvsweb/src/usr.bin/ssh/sshkey-xmss.c
Release NotesVendor Advisory
cvsweb.openbsd.org / cgi-bin/cvsweb/src/usr.bin/ssh/sshkey-xmss.c.diff
Patch
security.gentoo.org / glsa/201911-01
Third Party Advisory
security.netapp.com / advisory/ntap-20191024-0003
Third Party Advisory
ssd-disclosure.com / archives/4033/ssd-advisory-openssh-pre-auth-xmss-integer-overflow
ExploitThird Party Advisory
openssh.com / releasenotes.html
Release Notes
openwall.com / lists/oss-security/2019/10/09/1
Mailing ListThird Party Advisory