CVE-2016-6515
The auth_password function in auth-passwd.c in sshd in OpenSSH before 7.3 does not limit password lengths for password authentication, which allows remote attackers to cause a denial of service (crypt CPU consumption) via a long string.
Does this matter?
EPSS puts the probability of exploitation in the next 30 days at 58.6%, higher than 99% of all known CVEs. Patch or mitigate before the next change window.
Description
The auth_password function in auth-passwd.c in sshd in OpenSSH before 7.3 does not limit password lengths for password authentication, which allows remote attackers to cause a denial of service (crypt CPU consumption) via a long string.
- CVSS 3.0
- 7.5 HIGHCVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 58.57% probability · 99th percentile
- Public exploits
- 1 in Exploit-DB · first 7 December 2016
- CISA KEV
- Not listed
- Weakness
- CWE-20
- Affected
- openbsd/openssh · fedoraproject/fedora
- Source
- cve@mitre.org
EPSS moved from 46.2% on 21 September 2026 to 58.6% on 4 November 2026. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”.
Public exploits (1)
Entries in Exploit-DB that cite this CVE. Links go to the Exploit-DB page and to the file in the public repository; nothing is hosted here. A verified tick means the Exploit-DB team confirmed the exploit works against the stated version.
References
- http://openwall.com/lists/oss-security/2016/08/01/2Third Party Advisory, VDB Entry
- http://packetstormsecurity.com/files/140070/OpenSSH-7.2-Denial-Of-Service.html
- http://www.oracle.com/technetwork/security-advisory/cpuoct2017-3236626.html
- http://www.securityfocus.com/bid/92212
- http://www.securitytracker.com/id/1036487
- https://access.redhat.com/errata/RHSA-2017:2029
- https://cert-portal.siemens.com/productcert/pdf/ssa-412672.pdf
- https://cert-portal.siemens.com/productcert/pdf/ssa-676336.pdf
- https://github.com/openssh/openssh-portable/commit/fcd135c9df440bcd2d5870405ad3311743d78d97Issue Tracking, Patch
- https://lists.debian.org/debian-lts-announce/2018/09/msg00010.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/X2L6RW34VFNXYNVVN2CN73YAGJ5VMTFU/
- https://security.FreeBSD.org/advisories/FreeBSD-SA-17:06.openssh.asc
- https://security.netapp.com/advisory/ntap-20171130-0003/
- https://support.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbhf03779en_us
- https://www.exploit-db.com/exploits/40888/
- http://openwall.com/lists/oss-security/2016/08/01/2Third Party Advisory, VDB Entry
- http://packetstormsecurity.com/files/140070/OpenSSH-7.2-Denial-Of-Service.html
- http://www.oracle.com/technetwork/security-advisory/cpuoct2017-3236626.html
- http://www.securityfocus.com/bid/92212
- http://www.securitytracker.com/id/1036487
- https://access.redhat.com/errata/RHSA-2017:2029
- https://cert-portal.siemens.com/productcert/pdf/ssa-412672.pdf
- https://cert-portal.siemens.com/productcert/pdf/ssa-676336.pdf
- https://github.com/openssh/openssh-portable/commit/fcd135c9df440bcd2d5870405ad3311743d78d97Issue Tracking, Patch
- https://lists.debian.org/debian-lts-announce/2018/09/msg00010.html
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/X2L6RW34VFNXYNVVN2CN73YAGJ5VMTFU/
- https://security.FreeBSD.org/advisories/FreeBSD-SA-17:06.openssh.asc
- https://security.netapp.com/advisory/ntap-20171130-0003/
- https://support.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbhf03779en_us
- https://www.exploit-db.com/exploits/40888/
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.