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NVD / CVE Program· CNA mitre

CVE-2016-8858: The kex_input_kexinit function in kex.c in OpenSSH 6.x and 7.x through 7.3 allows remote attackers to cause a denial of service (memory…

HighCVSS 7.5 · v3.1—Proof of concept Fix available

Noroxi assessment

Priority: Monitor (action score 39/100)

  • Public proof-of-concept code exists (GitHub); there is no record of exploitation in the wild.
  • Probability of exploitation in the next 30 days: 29.4% (FIRST EPSS); higher than 98.2% 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) 1:7.3p1-2; openssh (openSUSE:Tumbleweed) 8.4p1-7.4; openssh (SUSE:Linux Enterprise Desktop 12 SP2) 7.2p2-66.1.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to openssh (Debian:12) 1:7.3p1-2; openssh (openSUSE:Tumbleweed) 8.4p1-7.4; openssh (SUSE:Linux Enterprise Desktop 12 SP2) 7.2p2-66.1 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 kex_input_kexinit function in kex.c in OpenSSH 6.x and 7.x through 7.3 allows remote attackers to cause a denial of service (memory consumption) by sending many duplicate KEXINIT requests. NOTE: a third party reports that "OpenSSH upstream does not consider this as a security issue."

Published
Dec 9, 2016
Updated
Jun 16, 2026
EPSS
29.4% · 98th percentile

Report tools

JSON

Action score

39

Monitor

Low priority for now.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
9 / 30 · 29.4%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • Proof of concept exists, no weaponized module
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

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When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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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.

VendorProduct
openbsdopenssh

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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.

  • openbsd openssh6.8
  • openbsd openssh6.9
  • openbsd openssh7.0
  • openbsd openssh7.1
  • openbsd openssh7.2
  • openbsd openssh7.3

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12opensshbefore 1:7.3p1-21:7.3p1-2
openSUSE:Tumbleweedopensshbefore 8.4p1-7.48.4p1-7.4
SUSE:Linux Enterprise Desktop 12 SP2opensshbefore 7.2p2-66.17.2p2-66.1
SUSE:Linux Enterprise Desktop 12 SP2openssh-askpass-gnomebefore 7.2p2-66.37.2p2-66.3
SUSE:Linux Enterprise Server 11 SP4opensshbefore 6.6p1-35.16.6p1-35.1
SUSE:Linux Enterprise Server 11 SP4openssh-askpass-gnomebefore 6.6p1-35.46.6p1-35.4
SUSE:Linux Enterprise Server 11-SECURITYopenssh-openssl1before 6.6p1-18.16.6p1-18.1
SUSE:Linux Enterprise Server 12 SP1opensshbefore 6.6p1-54.7.16.6p1-54.7.1
SUSE:Linux Enterprise Server 12 SP1openssh-askpass-gnomebefore 6.6p1-54.7.16.6p1-54.7.1
SUSE:OpenStack Cloud 5opensshbefore 6.2p2-0.40.16.2p2-0.40.1
SUSE:OpenStack Cloud 5openssh-askpass-gnomebefore 6.2p2-0.40.36.2p2-0.40.3

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
    68This week
  • CVE-2023-38408The PKCS#11 feature in ssh-agent in OpenSSH before 9.3p2 has an insufficiently trustworthy search path, leading to remote code execution if…
    63This week
  • CVE-2018-15473OpenSSH through 7.7 is prone to a user enumeration vulnerability due to not delaying bailout for an invalid authenticating user until after…
    60This week

Published before and after this one in the same product

  • ← EarlierCVE-2016-3115Mar 22, 2016 · Multiple CRLF injection vulnerabilities in session.c in sshd in OpenSSH before 7.2p2 allow remote authenticated users to bypass intended…
    36Monitor
  • ← EarlierCVE-2016-6515Aug 7, 2016 · The auth_password function in auth-passwd.c in sshd in OpenSSH before 7.3 does not limit password lengths for password authentication…
    48Plan
  • Later →CVE-2016-10009Jan 4, 2017 · Untrusted search path vulnerability in ssh-agent.c in ssh-agent in OpenSSH before 7.4 allows remote attackers to execute arbitrary local…
    40Plan

Remediation

Which version to upgrade to

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

Product / packageFixed versionSource
debian:openssh1:7.3p1-2 · Debian:12Package registry (OSV)
opensuse:openssh8.4p1-7.4 · openSUSE:TumbleweedPackage registry (OSV)
suse:openssh7.2p2-66.1 · SUSE:Linux Enterprise Desktop 12 SP2Package registry (OSV)
suse:openssh-askpass-gnome7.2p2-66.3 · SUSE:Linux Enterprise Desktop 12 SP2Package registry (OSV)
suse:openssh-openssl16.6p1-18.1 · SUSE:Linux Enterprise Server 11-SECURITYPackage registry (OSV)

Exploit status

Proof of concept available

A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.

Evidence

  • Proof-of-concept repository on GitHub ×1

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Proof-of-concept repository on GitHubstars:72016-11-03

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.

  1. First PoC-36 d
  2. Published
  3. TodayNov 15, 2026+3629 d

Patch and commit links

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

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

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
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-399 · Resource Management Errors

CVSS vector

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

nvd-secondary

Attack context

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

MITRE has no CAPEC/ATT&CK mapping for this CWE.

References

Show all references (12 more)

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

All records