Description
The x11_open_helper function in channels.c in ssh in OpenSSH before 6.9, when ForwardX11Trusted mode is not used, lacks a check of the refusal deadline for X connections, which makes it easier for remote attackers to bypass intended access restrictions via a connection outside of the permitted time window.
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 | 1:6.9p1-1 | — |
| Debian 13 | openssh | 1:6.9p1-1 | — |
| Debian 12 | openssh | 1:6.9p1-1 | — |
| Debian 8 | openssh | 1:6.7p1-5+deb8u6 | DLA-1500-1 |
| Debian 6.0 | openssh | 1:5.5p1-6+squeeze6 | DLA-288-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 14.04 LTS | openssh | 1:6.6p1-2ubuntu2.2 | USN-2710-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 6 | openssh +4 | 5.3p1-117.el6 | RHSA-2016:0741 |
| RHEL 6 | pam_ssh_agent_auth | 0.9.3-117.el6 | RHSA-2016:0741 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 12 | openssh +1 | 6.6p1-29.1 | SUSE-SU-2015:1544-1 |
| SLES 11 SP4 | openssh | 6.6p1-13.1 | SUSE-SU-2015:1695-1 |
| SLES 11 SP4 | openssh-askpass-gnome | 6.6p1-13.3 | SUSE-SU-2015:1695-1 |
| SLES 11 SP3 | openssh | 6.2p2-0.21.1 | SUSE-SU-2015:1581-1 |
| SLES 11 SP3 | openssh-askpass-gnome | 6.2p2-0.21.3 | SUSE-SU-2015:1581-1 |
| SLES 11 SP2 | openssh | 5.1p1-41.69.1 | SUSE-SU-2015:1840-1 |
| SLES 11 SP2 | openssh-askpass-gnome | 5.1p1-41.69.4 | SUSE-SU-2015:1840-1 |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 12 | openssh +1 | 6.6p1-29.1 | SUSE-SU-2015:1544-1 |
| SLES for SAP 11 SP4 | openssh | 6.6p1-13.1 | SUSE-SU-2015:1695-1 |
| SLES for SAP 11 SP4 | openssh-askpass-gnome | 6.6p1-13.3 | SUSE-SU-2015:1695-1 |
| SLES for SAP 11 SP3 | openssh | 6.2p2-0.21.1 | SUSE-SU-2015:1581-1 |
| SLES for SAP 11 SP3 | openssh-askpass-gnome | 6.2p2-0.21.3 | SUSE-SU-2015:1581-1 |
Advisories 10
- RHSA-2016:0741 Red Hat Security Advisory: openssh security, bug fix, and enhancement update Red Hat Security Advisories (RHSA) · Jun 26, 2026
- USN-2710-1 openssh vulnerabilities Ubuntu Security Notices (USN) · May 29, 2026
- DLA-288-1 openssh - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-1500-1 openssh - security update Debian Security (DSA / DLA) · Mar 9, 2026
- SUSE-SU-2015:1840-1 Security update for openssh SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2015:1581-1 Security update for openssh SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2015:1695-1 Security update for openssh SUSE / openSUSE Security Updates · Feb 4, 2026
- SUSE-SU-2015:1544-1 Security update for openssh SUSE / openSUSE Security Updates · May 2, 2025
- ICSA-22-349-21 Siemens SCALANCE X-200RNA Switch Devices CISA ICS & IT advisories · Dec 13, 2022
- SSA-412672 SSA-412672: Multiple OpenSSL and OpenSSH Vulnerabilities in SCALANCE X-200RNA Switch Devices before V3.2.7 Siemens ProductCERT · Dec 13, 2022
References
- USN-2710-2 vendor-advisory
- http://www.oracle.com/technetwork/topics/security/linuxbulletinapr2016-2952096.html
- https://security.netapp.com/advisory/ntap-20181023-0001/
- GLSA-201512-04 vendor-advisory
- https://anongit.mindrot.org/openssh.git/commit/?h=V_6_9&id=1bf477d3cdf1a864646d59820878783d42357a1d
- [oss-security] 20150701 Re: CVE Request: two security issues in openSSH 6.9 mailing-list
- RHSA-2016:0741 vendor-advisory
- 75525 vdb-entry
- 1032797 vdb-entry
- http://www.oracle.com/technetwork/topics/security/bulletinjan2016-2867206.html
- SUSE-SU-2015:1581 vendor-advisory
- http://www.openssh.com/txt/release-6.9
- [debian-lts-announce] 20180910 [SECURITY] [DLA 1500-1] openssh security update mailing-list
- USN-2710-1 vendor-advisory
- https://cert-portal.siemens.com/productcert/pdf/ssa-412672.pdf