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    CVE-2015-5600

    The kbdint_next_device function in auth2-chall.c in sshd in OpenSSH through 6.9 does not properly restrict the processing of keyboard-interactive devices within a single connection, which makes it easier for remote attackers to conduct brute-force attacks or cause a denial of service (CPU consumption) via a long and duplicative list in the ssh -oKbdInteractiveDevices option, as demonstrated by a modified client that provides a different password for each pam element on this list.

    Published:Jul 16, 2015
    Last Modified:May 27, 2026
    EPS:Aug 3, 2015
    EPSS Score:0.73594
    CVSS Score:8.1

    Affected Products

    Vendor
    Openbsd
    Product
    Openssh
    Vendor
    Redhat
    Product
    Enterprise Linux

    Exploits

    http://seclists.org/fulldisclosure/2015/Jul/92http://seclists.org/fulldisclosure/2015/Jul/92https://github.com/Abdirisaq-ali-aynab/openssh-vulnerability-assessmenthttps://github.com/Abdirisaq-ali-aynab/vulnerability-assessment

    Related CVEs

    CVE-2026-73283 (CVSS 2.5) — In sshd in OpenSSH before 10.5, the restrict keyword (in authorized_keys) was supposed to be applicable to tun…
    CVE-2026-73282 (CVSS 4.8) — In ssh in OpenSSH before 10.5, a use-after-free for realloc data can occur if a certain pair of remote-forward…
    CVE-2026-73281 (CVSS 3.5) — In ssh-agent in OpenSSH before 10.5, some operations can occur remotely but were intended to occur only locall…
    CVE-2026-60002 (CVSS 7.7) — ssh in OpenSSH before 10.4 can have a use-after-free when a server changes its host key during a key re-exchan…
    CVE-2026-60001 (CVSS 6.5) — sshd in OpenSSH before 10.4 does not always honor the minimum authentication delay.…
    CVE-2026-60000 (CVSS 3.7) — sshd in OpenSSH before 10.4 allows remote attackers to cause a denial of service (resource consumption from ex…
    CVE-2026-59999 (CVSS 5.9) — In sshd in OpenSSH before 10.4, DisableForwarding=yes was supposed to take precedence over PermitTunnel=yes, b…
    CVE-2026-59998 (CVSS 4.8) — sshd in OpenSSH before 10.4 has an undocumented security-relevant behavior: GSSAPIStrictAcceptorCheck has no v…
    CVE-2026-59997 (CVSS 4.2) — internal-sftp in sshd in OpenSSH before 10.4 recognizes only the first 9 command-line arguments, which can be …
    CVE-2026-59996 (CVSS 4.2) — scp in OpenSSH before 10.4 may place a file in the parent directory of an intended directory when the copy occ…

    References

    http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/auth2-chall.c
    http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/auth2-chall.c.diff?r1=1.42&r2=1.43&f=h
    http://kb.juniper.net/InfoCenter/index?page=content&id=JSA10697
    http://lists.apple.com/archives/security-announce/2015/Aug/msg00001.html
    http://lists.fedoraproject.org/pipermail/package-announce/2015-August/165170.html
    http://lists.fedoraproject.org/pipermail/package-announce/2015-July/162955.html
    http://lists.opensuse.org/opensuse-security-announce/2015-09/msg00017.html
    http://openwall.com/lists/oss-security/2015/07/23/4
    http://rhn.redhat.com/errata/RHSA-2016-0466.html
    http://seclists.org/fulldisclosure/2015/Jul/92
    http://www.oracle.com/technetwork/security-advisory/cpujul2016-2881720.html
    http://www.oracle.com/technetwork/security-advisory/cpujul2018-4258247.html
    http://www.oracle.com/technetwork/topics/security/bulletinoct2015-2511968.html
    http://www.oracle.com/technetwork/topics/security/linuxbulletinapr2016-2952096.html
    http://www.oracle.com/technetwork/topics/security/linuxbulletinoct2015-2719645.html
    http://www.oracle.com/technetwork/topics/security/ovmbulletinjul2016-3090546.html
    http://www.securityfocus.com/bid/75990
    http://www.securityfocus.com/bid/91787
    http://www.securityfocus.com/bid/92012
    http://www.securitytracker.com/id/1032988
    http://www.ubuntu.com/usn/USN-2710-1
    http://www.ubuntu.com/usn/USN-2710-2
    https://cert-portal.siemens.com/productcert/pdf/ssa-412672.pdf
    https://h20564.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c04952480
    https://h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05128992
    https://h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05157667
    https://kc.mcafee.com/corporate/index?page=content&id=SB10136
    https://kc.mcafee.com/corporate/index?page=content&id=SB10157
    https://lists.debian.org/debian-lts-announce/2018/09/msg00010.html
    https://security.gentoo.org/glsa/201512-04
    https://security.netapp.com/advisory/ntap-20151106-0001/
    https://support.apple.com/kb/HT205031
    https://www.arista.com/en/support/advisories-notices/security-advisories/1174-security-advisory-12
    http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/auth2-chall.c
    http://cvsweb.openbsd.org/cgi-bin/cvsweb/src/usr.bin/ssh/auth2-chall.c.diff?r1=1.42&r2=1.43&f=h
    http://kb.juniper.net/InfoCenter/index?page=content&id=JSA10697
    http://lists.apple.com/archives/security-announce/2015/Aug/msg00001.html
    http://lists.fedoraproject.org/pipermail/package-announce/2015-August/165170.html
    http://lists.fedoraproject.org/pipermail/package-announce/2015-July/162955.html
    http://lists.opensuse.org/opensuse-security-announce/2015-09/msg00017.html
    http://openwall.com/lists/oss-security/2015/07/23/4
    http://rhn.redhat.com/errata/RHSA-2016-0466.html
    http://seclists.org/fulldisclosure/2015/Jul/92
    http://www.oracle.com/technetwork/security-advisory/cpujul2016-2881720.html
    http://www.oracle.com/technetwork/security-advisory/cpujul2018-4258247.html
    http://www.oracle.com/technetwork/topics/security/bulletinoct2015-2511968.html
    http://www.oracle.com/technetwork/topics/security/linuxbulletinapr2016-2952096.html
    http://www.oracle.com/technetwork/topics/security/linuxbulletinoct2015-2719645.html
    http://www.oracle.com/technetwork/topics/security/ovmbulletinjul2016-3090546.html
    http://www.securityfocus.com/bid/75990
    http://www.securityfocus.com/bid/91787
    http://www.securityfocus.com/bid/92012
    http://www.securitytracker.com/id/1032988
    http://www.ubuntu.com/usn/USN-2710-1
    http://www.ubuntu.com/usn/USN-2710-2
    https://cert-portal.siemens.com/productcert/pdf/ssa-412672.pdf
    https://h20564.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c04952480
    https://h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05128992
    https://h20566.www2.hpe.com/portal/site/hpsc/public/kb/docDisplay?docId=emr_na-c05157667
    https://kc.mcafee.com/corporate/index?page=content&id=SB10136
    https://kc.mcafee.com/corporate/index?page=content&id=SB10157
    https://lists.debian.org/debian-lts-announce/2018/09/msg00010.html
    https://security.gentoo.org/glsa/201512-04
    https://security.netapp.com/advisory/ntap-20151106-0001/
    https://support.apple.com/kb/HT205031
    https://www.arista.com/en/support/advisories-notices/security-advisories/1174-security-advisory-12

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High