CVE-2019-16905

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

7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

EPSS

2.2% chance of exploitation in the next 30 days; higher than 82% of CVEs (scores of 2026-10-25)

CWE

CWE-190

Published

2019-10-09

Modified

2026-10-14

Record from

the NVD, synced 2026-10-19

Affected

• netapp:cloud_backup
• netapp:steelstore_cloud_integrated_storage
• openbsd:openssh
• siemens:scalance_x204rna_ecc_firmware
• siemens:scalance_x204rna_firmware

References

• https://bugzilla.suse.com/show_bug.cgi?id=1153537
• https://cert-portal.siemens.com/productcert/pdf/ssa-412672.pdf
• https://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/sshkey-xmss.c
• https://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/sshkey-xmss.c.diff?r1=1.5&r2=1.6&f=h
• https://security.gentoo.org/glsa/201911-01

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