CVE-2019-16905

Name: CVE-2019-16905
Creator: NVD / NIST
Published: 2019-10-09T20:15:23.503+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

HIGHCVSS 7.8/10EPSS 2.17%

Last modified Jun 17, 2026

CVE-2019-16905 is a high-severity vulnerability rated 7.8/10 on the CVSS scale. 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. EPSS estimates a 2.17% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 3.1

7.8/10

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

EPSS Probability

2.17%

80.0th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-190

Affected Software

Vendor	Product	Versions
Openbsd	Openssh	>= 7.7, <= 7.9
Openbsd	Openssh	>= 8.0, < 8.1
Netapp	Cloud Backup	All versions
Netapp	Steelstore Cloud Integrated Storage	All versions
Siemens	Scalance X204rna Firmware	< 3.2.7
Siemens	Scalance X204rna Ecc Firmware	< 3.2.7

References

https://bugzilla.suse.com/show_bug.cgi?id=1153537Issue Tracking, Third Party Advisory
https://cert-portal.siemens.com/productcert/pdf/ssa-412672.pdfThird Party Advisory
https://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/sshkey-xmss.cRelease Notes, Vendor Advisory
https://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/sshkey-xmss.c.diff?r1=1.5&r2=1.6&f=hPatch
https://security.gentoo.org/glsa/201911-01Third Party Advisory
https://security.netapp.com/advisory/ntap-20191024-0003/Third Party Advisory
https://ssd-disclosure.com/archives/4033/ssd-advisory-openssh-pre-auth-xmss-integer-overflowExploit, Third Party Advisory
https://www.openssh.com/releasenotes.htmlRelease Notes
https://www.openwall.com/lists/oss-security/2019/10/09/1Mailing List, Third Party Advisory
https://bugzilla.suse.com/show_bug.cgi?id=1153537Issue Tracking, Third Party Advisory
https://cert-portal.siemens.com/productcert/pdf/ssa-412672.pdfThird Party Advisory
https://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/sshkey-xmss.cRelease Notes, Vendor Advisory
https://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/sshkey-xmss.c.diff?r1=1.5&r2=1.6&f=hPatch
https://security.gentoo.org/glsa/201911-01Third Party Advisory
https://security.netapp.com/advisory/ntap-20191024-0003/Third Party Advisory
https://ssd-disclosure.com/archives/4033/ssd-advisory-openssh-pre-auth-xmss-integer-overflowExploit, Third Party Advisory
https://www.openssh.com/releasenotes.htmlRelease Notes
https://www.openwall.com/lists/oss-security/2019/10/09/1Mailing List, Third Party Advisory

Timeline

Published: Oct 9, 2019
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2019-16905?

How severe is CVE-2019-16905?

CVE-2019-16905 has a CVSS score of 7.8/10 (HIGH severity). The EPSS model estimates a 2.17% probability of exploitation in the next 30 days.

How do I fix CVE-2019-16905?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2019-16905?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST