Severity by source
AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Network-reachable SFTP server, no complexity, low-privilege auth required; purely availability impact via uncontrolled memory allocation.
Primary rating from Vendor (redhat).
CVSS VectorVendor: redhat
Lifecycle Timeline
2DescriptionCVE.org
A flaw was found in libssh. A remote authenticated client can issue SSH_FXP_READ requests with an arbitrarily large length, causing a libssh SFTP server to allocate excessive memory and potentially exhaust it through repeated requests.
AnalysisAI
Memory exhaustion in libssh's SFTP server subsystem allows authenticated remote clients to degrade or crash the service by sending SSH_FXP_READ requests specifying an arbitrarily large read length, causing the server to allocate unbounded memory for each request. The CVSS vector (PR:L) confirms exploitation requires valid credentials, limiting the attack surface to authenticated SFTP users. No public exploit code and no CISA KEV listing have been identified at time of analysis, though the low complexity and network-accessible attack path make this a realistic insider or credential-abuse scenario.
Technical ContextAI
libssh is a C library implementing the SSHv2 protocol, widely packaged in enterprise Linux distributions including Red Hat Enterprise Linux 8, 9, and 10 and Red Hat Hardened Images (per CPE data: cpe:2.3:a:red_hat:red_hat_enterprise_linux_*). The SFTP subsystem handles SSH_FXP_READ messages, which include a client-specified length field indicating how many bytes to return. CWE-789 (Uncontrolled Memory Allocation) identifies the root cause: the server fails to validate or cap this length field before allocating memory proportional to the client-supplied value. Repeated requests with large length values progressively exhaust server-side memory. This is a server-side flaw in the libssh SFTP daemon code path, not in the client library.
RemediationAI
Apply the vendor-released patch via Red Hat's standard update mechanism (yum/dnf update libssh) once a fixed package is published for the affected RHEL version; consult https://access.redhat.com/security/cve/CVE-2026-59844 for the current patch status and exact fixed package version. No specific fixed version number was confirmed in the provided data - do not assume a version without verifying against the Red Hat advisory. As an interim compensating control, restrict SFTP subsystem access to only explicitly authorized users using AllowUsers or Match blocks in sshd_config, which reduces the population of potential attackers at the cost of operational flexibility. Additionally, applying connection rate limiting (MaxStartups, MaxSessions in sshd_config) can slow repeated request flooding, though it will not prevent a single authenticated user from issuing many large-length reads within an established session. Monitoring for abnormal memory consumption on the SFTP daemon process can provide early detection.
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Same technique Information Disclosure
View allVendor StatusVendor
SUSE
Severity: Moderate| Product | Status |
|---|---|
| SUSE Linux Enterprise Module for Basesystem 15 SP7 | Affected |
| SUSE Linux Enterprise Server 15 SP7 | Affected |
| SUSE Linux Enterprise Desktop 15 SP7 | Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP7 | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP7 | Affected |
| SUSE Linux Enterprise Server 12 SP5-LTSS | Affected |
| SUSE Linux Enterprise Server 12 SP5-LTSS | Affected |
| SUSE Linux Enterprise Server 15 SP6-LTSS | Affected |
| SUSE Linux Enterprise Server 15 SP6-LTSS | Affected |
| SUSE Linux Enterprise Server LTSS Extended Security 12 SP5 | Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP6 | Affected |
| SUSE Linux Enterprise Desktop 15 SP7 | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP7 | Affected |
| SUSE Linux Enterprise Micro 5.3 | Affected |
| SUSE Linux Enterprise Micro 5.4 | Affected |
| SUSE Linux Enterprise Micro 5.5 | Affected |
| SUSE Linux Enterprise Module for Basesystem 15 SP7 | Affected |
| SUSE Linux Enterprise Server 15 SP7 | Affected |
| SUSE Linux Enterprise Server 16.0 | Affected |
| SUSE Linux Enterprise Server 16.1 | Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP7 | Affected |
| SUSE Linux Enterprise Server for SAP applications 16.0 | Affected |
| SUSE Linux Enterprise Server for SAP applications 16.1 | Affected |
| SUSE Linux Micro 6.0 | Affected |
| SUSE Linux Micro 6.1 | Affected |
| SUSE Linux Micro 6.2 | Affected |
| openSUSE Leap 16.0 | Affected |
| SUSE Linux Enterprise High Performance Computing 12 SP5 | Not-Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP4 | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP5 | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP5-LTSS | Affected |
| SUSE Linux Enterprise Module for Basesystem 15 SP4 | Affected |
| SUSE Linux Enterprise Module for Basesystem 15 SP5 | Affected |
| SUSE Linux Enterprise Module for Basesystem 15 SP6 | Affected |
| SUSE Linux Enterprise Server 12 SP5 | Affected |
| SUSE Linux Enterprise Server 12 SP5-LTSS | Affected |
| SUSE Linux Enterprise Server 12 SP5-LTSS Extended Security | Not-Affected |
| SUSE Linux Enterprise Server 15 SP4 | Affected |
| SUSE Linux Enterprise Server 15 SP4-LTSS | Affected |
| SUSE Linux Enterprise Server 15 SP5 | Affected |
| SUSE Linux Enterprise Server 15 SP5-LTSS | Affected |
| SUSE Linux Enterprise Server 15 SP6 | Affected |
| SUSE Linux Enterprise Server 15 SP6-LTSS | Affected |
| SUSE Linux Enterprise Server LTSS Extended Security 12 SP5 | Affected |
| SUSE Linux Enterprise Server for SAP Applications 12 SP5 | Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP6 | Affected |
| SUSE Manager Proxy 4.3 | Affected |
| SUSE Manager Proxy LTS 4.3 | Affected |
| SUSE Manager Retail Branch Server 4.3 | Affected |
| SUSE Manager Retail Branch Server LTS 4.3 | Affected |
| SUSE Manager Server 4.3 | Affected |
| SUSE Manager Server LTS 4.3 | Affected |
| SUSE CaaS Platform 4.0 | Affected |
| SUSE Enterprise Storage 6 | Affected |
| SUSE Enterprise Storage 7 | Affected |
| SUSE Enterprise Storage 7.1 | Affected |
| SUSE Linux Enterprise Desktop 12 | Not-Affected |
| SUSE Linux Enterprise Desktop 12 SP1 | Not-Affected |
| SUSE Linux Enterprise Desktop 12 SP2 | Not-Affected |
| SUSE Linux Enterprise Desktop 12 SP3 | Not-Affected |
| SUSE Linux Enterprise Desktop 12 SP4 | Not-Affected |
| SUSE Linux Enterprise Desktop 15 SP1 | Affected |
| SUSE Linux Enterprise Desktop 15 SP2 | Affected |
| SUSE Linux Enterprise Desktop 15 SP3 | Affected |
| SUSE Linux Enterprise Desktop 15 SP4 | Affected |
| SUSE Linux Enterprise Desktop 15 SP5 | Affected |
| SUSE Linux Enterprise Desktop 15 SP6 | Affected |
| SUSE Linux Enterprise High Performance Computing 12 SP4 | Not-Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP1 | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP1-ESPOS | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP1-LTSS | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP2 | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP2-ESPOS | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP2-LTSS | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP3 | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP3-ESPOS | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP3-LTSS | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP4-ESPOS | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP5-ESPOS | Affected |
| SUSE Linux Enterprise High Performance Computing 15 SP6 | Affected |
| SUSE Linux Enterprise Micro 5.0 | Affected |
| SUSE Linux Enterprise Micro 5.1 | Affected |
| SUSE Linux Enterprise Micro 5.2 | Affected |
| SUSE Linux Enterprise Module for Basesystem 15 SP1 | Affected |
| SUSE Linux Enterprise Module for Basesystem 15 SP2 | Affected |
| SUSE Linux Enterprise Module for Basesystem 15 SP3 | Affected |
| SUSE Linux Enterprise Real Time 15 SP2 | Affected |
| SUSE Linux Enterprise Real Time 15 SP3 | Affected |
| SUSE Linux Enterprise Real Time 15 SP4 | Affected |
| SUSE Linux Enterprise Server 12 | Not-Affected |
| SUSE Linux Enterprise Server 12 SP1 | Not-Affected |
| SUSE Linux Enterprise Server 12 SP2 | Not-Affected |
| SUSE Linux Enterprise Server 12 SP3 | Not-Affected |
| SUSE Linux Enterprise Server 12 SP4 | Not-Affected |
| SUSE Linux Enterprise Server 12 SP4-ESPOS | Not-Affected |
| SUSE Linux Enterprise Server 12 SP4-LTSS | Not-Affected |
| SUSE Linux Enterprise Server 15 SP1 | Affected |
| SUSE Linux Enterprise Server 15 SP1-BCL | Affected |
| SUSE Linux Enterprise Server 15 SP1-LTSS | Affected |
| SUSE Linux Enterprise Server 15 SP2 | Affected |
| SUSE Linux Enterprise Server 15 SP2-BCL | Affected |
| SUSE Linux Enterprise Server 15 SP2-LTSS | Affected |
| SUSE Linux Enterprise Server 15 SP3 | Affected |
| SUSE Linux Enterprise Server 15 SP3-BCL | Affected |
| SUSE Linux Enterprise Server 15 SP3-LTSS | Affected |
| SUSE Linux Enterprise Server for SAP Applications 12 | Not-Affected |
| SUSE Linux Enterprise Server for SAP Applications 12 SP1 | Not-Affected |
| SUSE Linux Enterprise Server for SAP Applications 12 SP2 | Not-Affected |
| SUSE Linux Enterprise Server for SAP Applications 12 SP3 | Not-Affected |
| SUSE Linux Enterprise Server for SAP Applications 12 SP4 | Not-Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP1 | Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP2 | Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP3 | Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP4 | Affected |
| SUSE Linux Enterprise Server for SAP Applications 15 SP5 | Affected |
| SUSE Linux Enterprise Software Development Kit 12 | Not-Affected |
| SUSE Linux Enterprise Software Development Kit 12 SP1 | Not-Affected |
| SUSE Linux Enterprise Software Development Kit 12 SP2 | Not-Affected |
| SUSE Linux Enterprise Software Development Kit 12 SP3 | Not-Affected |
| SUSE Linux Enterprise Software Development Kit 12 SP4 | Not-Affected |
| SUSE Linux Enterprise Software Development Kit 12 SP5 | Affected |
| SUSE Linux Enterprise Workstation Extension 12 | Not-Affected |
| SUSE Linux Enterprise Workstation Extension 12 SP1 | Not-Affected |
| SUSE Linux Enterprise Workstation Extension 12 SP2 | Not-Affected |
| SUSE Linux Enterprise Workstation Extension 12 SP3 | Not-Affected |
| SUSE Manager Proxy 4.0 | Affected |
| SUSE Manager Proxy 4.1 | Affected |
| SUSE Manager Proxy 4.2 | Affected |
| SUSE Manager Retail Branch Server 4.0 | Affected |
| SUSE Manager Retail Branch Server 4.1 | Affected |
| SUSE Manager Retail Branch Server 4.2 | Affected |
| SUSE Manager Server 4.0 | Affected |
| SUSE Manager Server 4.1 | Affected |
| SUSE Manager Server 4.2 | Affected |
| SUSE OpenStack Cloud 9 | Not-Affected |
| SUSE OpenStack Cloud Crowbar 9 | Not-Affected |
| openSUSE Leap 15.3 | Affected |
| openSUSE Leap 15.4 | Affected |
| openSUSE Leap 15.5 | Affected |
| openSUSE Leap 15.6 | Affected |
| openSUSE Leap Micro 5.2 | Affected |
| openSUSE Leap Micro 5.3 | Affected |
| openSUSE Leap Micro 5.4 | Affected |
| openSUSE Leap Micro 5.5 | Affected |
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External POC / Exploit Code
Leaving vuln.today
EUVD-2026-46179
GHSA-qp28-hpg5-j7xc