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.
Fix
Patch, vendor advisory and mitigation references on NVD 4
- https://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/sshkey-xmss.c Release 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=h Patch
- https://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/sshkey-xmss.c Release 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=h Patch
Every line above is quoted from NVD, CISA, Microsoft, the vendor's own advisory or DISA; nothing is generated.
Change history 1
- First seenCVSS 7.8 · openbsd, netapp, siemensNVD modified 2026-10-14 07:16
Affected (CPE criteria) 5
cpe:2.3:a:openbsd:openssh:*:*:*:*:*:*:*:*cpe:2.3:a:netapp:cloud_backup:-:*:*:*:*:*:*:*cpe:2.3:a:netapp:steelstore_cloud_integrated_storage:-:*:*:*:*:*:*:*cpe:2.3:o:siemens:scalance_x204rna_firmware:*:*:*:*:*:*:*:*cpe:2.3:o:siemens:scalance_x204rna_ecc_firmware:*:*:*:*:*:*:*:*
References 20
- https://bugzilla.suse.com/show_bug.cgi?id=1153537 Issue Tracking, Third 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 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=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 Exploit, Third Party Advisory
- https://www.openssh.com/releasenotes.html Release Notes
- https://www.openwall.com/lists/oss-security/2019/10/09/1 Mailing List, Third Party Advisory
- https://bugzilla.suse.com/show_bug.cgi?id=1153537 Issue Tracking, Third 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 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=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 Exploit, Third Party Advisory
- https://www.openssh.com/releasenotes.html Release Notes
- https://www.openwall.com/lists/oss-security/2019/10/09/1 Mailing List, Third Party Advisory
- https://cert-portal.siemens.com/productcert/html/ssa-398330.html
- https://cert-portal.siemens.com/productcert/html/ssa-412672.html