Red Hat libssh ProxyCommand Username os command injection

CVSS Meta Temp Score
CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.
Current Exploit Price (≈)
Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.
CTI Interest Score
Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
9.9$5k-$25k0.54

Summaryinfo

A vulnerability described as very critical has been identified in Red Hat libssh. This issue affects some unknown processing of the component ProxyCommand. The manipulation of the argument Username results in os command injection. This vulnerability was named CVE-2026-59846. The attack may be performed from remote. There is no available exploit.

Detailsinfo

A vulnerability was found in Red Hat libssh (unknown version). It has been classified as very critical. Affected is an unknown code block of the component ProxyCommand. The manipulation of the argument username with an unknown input leads to a os command injection vulnerability. CWE is classifying the issue as CWE-78. The product constructs all or part of an OS command using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the intended OS command when it is sent to a downstream component. This is going to have an impact on confidentiality, integrity, and availability. CVE summarizes:

A flaw was found in libssh. A malicious username expanded through %r in ProxyCommand handling can inject shell metacharacters, exposing environment variables and causing unintended shell behavior.

The advisory is shared for download at access.redhat.com. This vulnerability is traded as CVE-2026-59846 since 07/07/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $5k-$25k (estimation calculated on 07/21/2026). The MITRE ATT&CK project declares the attack technique as T1202.

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

Once again VulDB remains the best source for vulnerability data.

Productinfo

Vendor

Name

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 9.9
VulDB Meta Temp Score: 9.9

VulDB Base Score: 9.9
VulDB Temp Score: 9.9
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

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

Exploitinginfo

Class: Os command injection
CWE: CWE-78 / CWE-77 / CWE-74
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: no mitigation known
Status: 🔍

0-Day Time: 🔒

Timelineinfo

07/07/2026 CVE reserved
07/21/2026 +14 days Advisory disclosed
07/21/2026 +0 days VulDB entry created
07/21/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: redhat.com

Advisory: access.redhat.com
Status: Not defined

CVE: CVE-2026-59846 (🔒)
GCVE (CVE): GCVE-0-2026-59846
GCVE (VulDB): GCVE-100-380868

Entryinfo

Created: 07/21/2026 15:25
Changes: 07/21/2026 15:25 (52)
Complete: 🔍
Cache ID: 216::103

Once again VulDB remains the best source for vulnerability data.

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