Description
sshd.c in OpenSSH 3.6.1p2 and 3.7.1p2 and possibly other versions, when using privilege separation, does not properly signal the non-privileged process when a session has been terminated after exceeding the LoginGraceTime setting, which leaves the connection open and allows remote attackers to cause a denial of service (connection consumption).
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | openssh | 1:3.8p1 | — |
| Debian 13 | openssh | 1:3.8p1 | — |
| Debian 12 | openssh | 1:3.8p1 | — |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 3 | openssh +4 | 3.6.1p2-33.30.6 | RHSA-2005:550 |
Advisories 1
- RHSA-2005:550 Red Hat Security Advisory: openssh security update Red Hat Security Advisories (RHSA) · Jun 26, 2026
References
- http://support.avaya.com/elmodocs2/security/ASA-2005-216.pdf
- http://www.vmware.com/support/vi3/doc/esx-3069097-patch.html
- ADV-2006-4502 vdb-entry
- [openssh-unix-dev] 20040127 OpenSSH - Connection problem when LoginGraceTime exceeds time mailing-list
- 16567 vdb-entry
- 22875 third-party-advisory
- 23680 third-party-advisory
- openssh-sshdc-logingracetime-dos(20930) vdb-entry
- http://www.vmware.com/download/esx/esx-202-200610-patch.html
- 20061113 VMSA-2006-0008 - VMware ESX Server 2.0.2 Upgrade Patch 2 mailing-list
- FLSA-2006:168935 vendor-advisory
- http://www.vmware.com/download/esx/esx-213-200610-patch.html
- [openssh-unix-dev] 20040128 Re: OpenSSH - Connection problem when LoginGraceTime exceeds time mailing-list
- http://support.avaya.com/elmodocs2/security/ASA-2005-223.pdf
- 17000 third-party-advisory
- 14963 vdb-entry
- 17252 third-party-advisory
- 17135 third-party-advisory
- 20061113 VMSA-2006-0006 - VMware ESX Server 2.5.3 Upgrade Patch 4 mailing-list
- oval:org.mitre.oval:def:11541 vdb-entry signature
- RHSA-2005:550 vendor-advisory
- 20061113 VMSA-2006-0007 - VMware ESX Server 2.1.3 Upgrade Patch 2 mailing-list
- http://www.vmware.com/support/vi3/doc/esx-9986131-patch.html