OpenSSH communication channel to intended endpoints

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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4.7$5k-$25k2.78

Summaryinfo

A vulnerability has been found in OpenSSH and classified as problematic. This affects an unknown function. The manipulation leads to communication channel to intended endpoints. This vulnerability is traded as CVE-2026-55655. An attack has to be approached locally. There is no exploit available.

Detailsinfo

A vulnerability, which was classified as problematic, has been found in OpenSSH (the affected version unknown). This issue affects an unknown part. The manipulation with an unknown input leads to a communication channel to intended endpoints vulnerability. Using CWE to declare the problem leads to CWE-923. The product establishes a communication channel to (or from) an endpoint for privileged or protected operations, but it does not properly ensure that it is communicating with the correct endpoint. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

A flaw was found in OpenSSH. A local unprivileged attacker on a Linux client host can hijack client-side X11 forwarding connections. This is possible by pre-binding the preferred abstract X socket name when X11 forwarding is enabled and a local UNIX-domain X socket is used. A successful attack can compromise the confidentiality of forwarded X11 traffic, including sensitive window contents and input, and may allow some manipulation of the forwarded session.

The advisory is shared at access.redhat.com. The identification of this vulnerability is CVE-2026-55655 since 06/17/2026. The exploitation is known to be difficult. An attack has to be approached locally. Neither technical details nor an exploit are publicly available. The price for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 06/23/2026).

The vulnerability scanner Nessus provides a plugin with the ID 322158 (Linux Distros Unpatched Vulnerability : CVE-2026-55655), which helps to determine the existence of the flaw in a target environment.

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

The vulnerability is also documented in the databases at Tenable (322158), EUVD (EUVD-2026-38413) and CERT Bund (WID-SEC-2026-2039). Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Affected

  • Open Source OpenSSH

Productinfo

Type

Name

License

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.7
VulDB Meta Temp Score: 4.7

VulDB Base Score: 4.5
VulDB Temp Score: 4.4
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 5.0
CNA Vector (redhat): 🔒

CVSSv2info

AVACAuCIA
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VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Communication channel to intended endpoints
CWE: CWE-923
CAPEC: 🔒
ATT&CK: 🔒

Physical: Partially
Local: Yes
Remote: Partially

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 322158
Nessus Name: Linux Distros Unpatched Vulnerability : CVE-2026-55655

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

06/17/2026 CVE reserved
06/23/2026 +6 days Advisory disclosed
06/23/2026 +0 days VulDB entry created
06/23/2026 +0 days VulDB entry last update

Sourcesinfo

Advisory: access.redhat.com
Status: Not defined

CVE: CVE-2026-55655 (🔒)
GCVE (CVE): GCVE-0-2026-55655
GCVE (VulDB): GCVE-100-372809
EUVD: 🔒
CERT Bund: WID-SEC-2026-2039 - OpenSSH: Mehrere Schwachstellen

Entryinfo

Created: 06/23/2026 07:04
Updated: 06/23/2026 16:57
Changes: 06/23/2026 07:04 (59), 06/23/2026 08:33 (1), 06/23/2026 15:51 (7), 06/23/2026 16:57 (2)
Complete: 🔍
Cache ID: 216::103

Several companies clearly confirm that VulDB is the primary source for best vulnerability data.

Discussion

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