Home/CVE/OpenSSH before 10.3 omits connection multiplexing confirmation for proxy-mode multiplexing sessions.
CVE

CVE-2026-35388

OpenSSH before 10.3 omits connection multiplexing confirmation for proxy-mode multiplexing sessions.

OpenSSH before 10.3 omits connection multiplexing confirmation for proxy-mode multiplexing sessions.

LOW · CVSS 2.5 EPSS 0.00015
Monitor
  • No active-exploitation, high-EPSS, or public-exploit signals - routine patching cadence
Sigma rules2 YARA rules0
⬡

Weakness Classification

CWE-420Unprotected Alternate Channel
▤

Affected Products & Versions

1
openbsd openssh< 10.3
◈

Sigma Hunt Rules

2
Exact rules name this CVE ID. Product rules name an affected product in their title. Related rules cover techniques used by actors who exploited this CVE. Showing the most relevant matches; the complete related set is on the full drill-down.
productmediumSuspicious OpenSSH Daemon Error
productmediumOpenSSH Server Listening On Socket
▣

Scoring & Timeline

2.5
LOW · CVSS v3.1 · cve@mitre.org
View on NVD
Attack Vector
Network Adjacent Local Physical
Attack Complexity
Low High
Privileges Required
None Low High
User Interaction
None Required
Scope
Unchanged Changed
Confidentiality
None Low High
Integrity
None Low High
Availability
None Low High
Published to NVD02 Apr 2026 · 05:16 PM
CVSS VectorCVSS:3.1/AV:L/AC:H/PR:N/UI:R/S:U/C:N/I:L/A:N
SSVC triage · cisa-vulnrichment
Exploitation
none
Automatable
no
Technical impact
partial
SSVC asks the questions that actually drive patch urgency: is it being exploited, can attacks be automated, and how total is the impact.
⚑

Vendor Advisories

10
rhsaRHSA-2026:19219Important
rhsaRHSA-2026:19069Important
rhsaRHSA-2026:16059Important
rhsaRHSA-2026:14937Important
rhsaRHSA-2026:13383Important
🔗

References & Sources

3
Source URLs (vendor pages, mailing lists, write-ups). Exploit/PoC links are in their own section above to avoid duplication.
https://marc.info/?l=openssh-unix-dev&m=177513443901484&w=2Third Party Advisory
https://www.openssh.org/releasenotes.html#10.3p1Release Notes
https://www.openwall.com/lists/oss-security/2026/04/02/3Third Party Advisory
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