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Vulnerability record · CVE-2019-16905 · published 9 October 2019

CVE-2019-16905: Openbsd openssh integer overflow vulnerability

Openbsd · Openssh

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.

7.8 CVSS 3.1 High EPSS 2.2% · top 18.5% CWE-190 · Integer overflow
7.8CVSS 3.1 base score, v2 4.4
2.2%EPSS exploitation probability, 30 days
NoNot in CISA KEV
5Affected product versions listed by NVD
18References, 2 tagged exploit
17 Jun 2026Last modified by NVD

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.

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

Affected products

5 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://bugzilla.suse.com/show_bug.cgi?id=1153537 Issue TrackingThird Party Advisory
https://cert-portal.siemens.com/productcert/pdf/ssa-412672.pdf Third Party Advisory
https://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/sshkey-xmss.c Release NotesVendor Advisory
https://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/sshkey-xmss.c.diff?r1=1.5&r2=1.6&f=h Patch
https://security.gentoo.org/glsa/201911-01 Third 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-overflow ExploitThird Party Advisory
https://www.openssh.com/releasenotes.html Release Notes
https://www.openwall.com/lists/oss-security/2019/10/09/1 Mailing ListThird Party Advisory
https://bugzilla.suse.com/show_bug.cgi?id=1153537 Issue TrackingThird Party Advisory
https://cert-portal.siemens.com/productcert/pdf/ssa-412672.pdf Third Party Advisory
https://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/sshkey-xmss.c Release NotesVendor Advisory
https://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/sshkey-xmss.c.diff?r1=1.5&r2=1.6&f=h Patch
https://security.gentoo.org/glsa/201911-01 Third 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-overflow ExploitThird Party Advisory
https://www.openssh.com/releasenotes.html Release Notes
https://www.openwall.com/lists/oss-security/2019/10/09/1 Mailing ListThird Party Advisory

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Source: NIST National Vulnerability Database (record CVE-2019-16905), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.