NVD / CVE Program· CNA redhat

CVE-2016-1908: The client in OpenSSH before 7.2 mishandles failed cookie generation for untrusted X11 forwarding and relies on the local X11 server for…

CriticalCVSS 9.8 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Plan (action score 43/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 13.7% (FIRST EPSS); higher than 96.5% of all records.
Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
According to CISA the attack is automatable: targets can be found by mass scanning.
Fixed version: openssh (Debian:12) 1:7.2p1-1; openssh (Debian:8) 1:6.7p1-5+deb8u6; openssh (Red Hat:enterprise_linux:6::client) 0:5.3p1-117.el6.

Add it to your regular patch cycle. Upgrade to openssh (Debian:12) 1:7.2p1-1; openssh (Debian:8) 1:6.7p1-5+deb8u6; openssh (Red Hat:enterprise_linux:6::client) 0:5.3p1-117.el6 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

The client in OpenSSH before 7.2 mishandles failed cookie generation for untrusted X11 forwarding and relies on the local X11 server for access-control decisions, which allows remote X11 clients to trigger a fallback and obtain trusted X11 forwarding privileges by leveraging configuration issues on this X11 server, as demonstrated by lack of the SECURITY extension on this X11 server.

Published: Apr 11, 2017
Updated: Jun 16, 2026
EPSS: 13.7% · 96th percentile
CWE: CWE-287

Report tools

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Action score

Plan

Add it to your regular patch cycle.

CVSS: 39 / 40 · 9.8 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 4 / 30 · 13.7%

CISA SSVC decision

Exploitation: none
Automatable: yes
Technical impact: total

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

Not in KEV: no record of exploitation in the wild
No public exploit code on record
A fix has been released

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

Vendor	Product	CPE
openbsd	openssh	cpe:2.3:a:openbsd:openssh
debian	debian linux	cpe:2.3:o:debian:debian_linux
oracle	linux	cpe:2.3:o:oracle:linux
redhat	enterprise linux desktop	cpe:2.3:o:redhat:enterprise_linux_desktop
redhat	enterprise linux eus	cpe:2.3:o:redhat:enterprise_linux_eus
redhat	enterprise linux server	cpe:2.3:o:redhat:enterprise_linux_server
redhat	enterprise linux server aus	cpe:2.3:o:redhat:enterprise_linux_server_aus
redhat	enterprise linux server tus	cpe:2.3:o:redhat:enterprise_linux_server_tus
redhat	enterprise linux workstation	cpe:2.3:o:redhat:enterprise_linux_workstation

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Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

debian debian linux8.0
openbsd opensshbefore 7.2
oracle linux6
oracle linux7
redhat enterprise linux desktop6.0
redhat enterprise linux desktop7.0
redhat enterprise linux eus7.2
redhat enterprise linux eus7.3

+12 more rows

redhat enterprise linux eus7.4
redhat enterprise linux eus7.5
redhat enterprise linux eus7.6
redhat enterprise linux eus7.7
redhat enterprise linux server6.0
redhat enterprise linux server7.0
redhat enterprise linux server aus7.2
redhat enterprise linux server aus7.3
redhat enterprise linux server aus7.4
redhat enterprise linux server aus7.6
redhat enterprise linux server aus7.7
redhat enterprise linux server tus7.2

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Ecosystem	Package	Affected range	Fix
Debian:12	openssh	before 1:7.2p1-1	1:7.2p1-1
Debian:8	openssh	before 1:6.7p1-5+deb8u6	1:6.7p1-5+deb8u6
Red Hat:enterprise_linux:6::client	openssh	before 0:5.3p1-117.el6	0:5.3p1-117.el6
Red Hat:enterprise_linux:6::client	openssh-askpass	before 0:5.3p1-117.el6	0:5.3p1-117.el6
Red Hat:enterprise_linux:6::client	openssh-clients	before 0:5.3p1-117.el6	0:5.3p1-117.el6
Red Hat:enterprise_linux:6::client	openssh-debuginfo	before 0:5.3p1-117.el6	0:5.3p1-117.el6
Red Hat:enterprise_linux:6::client	openssh-ldap	before 0:5.3p1-117.el6	0:5.3p1-117.el6
Red Hat:enterprise_linux:6::client	openssh-server	before 0:5.3p1-117.el6	0:5.3p1-117.el6
Red Hat:enterprise_linux:6::client	pam_ssh_agent_auth	before 0:0.9.3-117.el6	0:0.9.3-117.el6
Red Hat:enterprise_linux:7::client	openssh	before 0:6.6.1p1-25.el7_2	0:6.6.1p1-25.el7_2
Red Hat:enterprise_linux:7::client	openssh-askpass	before 0:6.6.1p1-25.el7_2	0:6.6.1p1-25.el7_2
Red Hat:enterprise_linux:7::client	openssh-clients	before 0:6.6.1p1-25.el7_2	0:6.6.1p1-25.el7_2
Red Hat:enterprise_linux:7::client	openssh-debuginfo	before 0:6.6.1p1-25.el7_2	0:6.6.1p1-25.el7_2
Red Hat:enterprise_linux:7::client	openssh-keycat	before 0:6.6.1p1-25.el7_2	0:6.6.1p1-25.el7_2
Red Hat:enterprise_linux:7::client	openssh-ldap	before 0:6.6.1p1-25.el7_2	0:6.6.1p1-25.el7_2
Red Hat:enterprise_linux:7::client	openssh-server	before 0:6.6.1p1-25.el7_2	0:6.6.1p1-25.el7_2
Red Hat:enterprise_linux:7::client	openssh-server-sysvinit	before 0:6.6.1p1-25.el7_2	0:6.6.1p1-25.el7_2
Red Hat:enterprise_linux:7::client	pam_ssh_agent_auth	before 0:0.9.3-9.25.el7_2	0:0.9.3-9.25.el7_2
SUSE:Linux Enterprise Desktop 12	openssh	before 6.6p1-42.1	6.6p1-42.1
SUSE:Linux Enterprise Desktop 12	openssh-askpass-gnome	before 6.6p1-42.1	6.6p1-42.1
SUSE:Linux Enterprise Server 11 SP4	openssh	before 6.6p1-21.1	6.6p1-21.1
SUSE:Linux Enterprise Server 11 SP4	openssh-askpass-gnome	before 6.6p1-21.3	6.6p1-21.3
SUSE:Linux Enterprise Server 11-SECURITY	openssh-openssl1	before 6.6p1-15.1	6.6p1-15.1
SUSE:OpenStack Cloud 5	openssh	before 6.2p2-0.33.2	6.2p2-0.33.2

Same product

openbsd: all records

Other highest-scoring records for the same primary product.

CVE-2026-123158sshd in OpenSSH before 10.6p2 on Linux, when musl libc is used without PAM, lacks a workaround for a password authentication bypass…KEV
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63This week
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Published before and after this one in the same product

← EarlierCVE-2016-10012Jan 4, 2017 · The shared memory manager (associated with pre-authentication compression) in sshd in OpenSSH before 7.4 does not ensure that a bounds…
31Monitor
← EarlierCVE-2016-6210Feb 13, 2017 · sshd in OpenSSH before 7.3, when SHA256 or SHA512 are used for user password hashing, uses BLOWFISH hashing on a static password when the…
60This week
Later →CVE-2017-15906Oct 25, 2017 · The process_open function in sftp-server.c in OpenSSH before 7.6 does not properly prevent write operations in readonly mode, which allows…
22Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / package	Fixed version	Source
debian:openssh	1:7.2p1-1 · Debian:12	Package registry (OSV)
red hat:openssh	0:6.6.1p1-25.el7_2 · Red Hat:enterprise_linux:7::client	Package registry (OSV)
red hat:openssh-askpass	0:6.6.1p1-25.el7_2 · Red Hat:enterprise_linux:7::client	Package registry (OSV)
red hat:openssh-clients	0:6.6.1p1-25.el7_2 · Red Hat:enterprise_linux:7::client	Package registry (OSV)
red hat:openssh-debuginfo	0:6.6.1p1-25.el7_2 · Red Hat:enterprise_linux:7::client	Package registry (OSV)
red hat:openssh-keycat	0:6.6.1p1-25.el7_2 · Red Hat:enterprise_linux:7::client	Package registry (OSV)
red hat:openssh-ldap	0:6.6.1p1-25.el7_2 · Red Hat:enterprise_linux:7::client	Package registry (OSV)
red hat:openssh-server	0:6.6.1p1-25.el7_2 · Red Hat:enterprise_linux:7::client	Package registry (OSV)
red hat:openssh-server-sysvinit	0:6.6.1p1-25.el7_2 · Red Hat:enterprise_linux:7::client	Package registry (OSV)
red hat:pam_ssh_agent_auth	0:0.9.3-9.25.el7_2 · Red Hat:enterprise_linux:7::client	Package registry (OSV)
suse:openssh	6.6p1-42.1 · SUSE:Linux Enterprise Desktop 12	Package registry (OSV)
suse:openssh-askpass-gnome	6.6p1-42.1 · SUSE:Linux Enterprise Desktop 12	Package registry (OSV)
suse:openssh-openssl1	6.6p1-15.1 · SUSE:Linux Enterprise Server 11-SECURITY	Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

anongit.mindrot.orgpatch

Not on record for this CVE: EPSS history · researcher credit · variant or chain candidate · public bounty program.

Technical details

Attack conditions

Anyone who can reach it over the internet can trigger it.
No account or password is required.
No user action is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality: high · data can be read
Integrity: high · data or configuration can be modified
Availability: high · the service can be disrupted

Attack vector: Network
Attack complexity: Low
Privileges required: None
User interaction: None
Scope: Unchanged
Confidentiality impact: High
Integrity impact: High
Availability impact: High

Weakness class (CWE)

CWE-287 · Improper Authentication

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

nvd-primary

Root cause

Authentication is added route by route instead of being enforced in one place. When a route added later bypasses the shared middleware, the session check never runs for it.

The bug in code

The whole CWE-287 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1app.use("/admin", requireSession, adminRouter);
2

3// Route added later skips the middleware
4app.post("/admin-api/config", updateConfig);

Fixed

1const admin = express.Router();
2admin.use(requireSession, requireRole("admin"));
3

4admin.post("/config", updateConfig);
5app.use("/admin", admin);

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Attack patterns (CAPEC)

ATT&CK techniques

Change log (1)

Fix✗ → ✓Sep 28, 2026, 10:45 PM UTC

For records you follow, these changes also arrive as notifications. →

References

openwall.com/lists/oss-security/2016/01/15/13

Show all references (11 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records