Unbounded Memory DoS in libssh SFTP Client via Unknown Request IDs
CVE-2026-59848 Published on July 21, 2026

Libssh: libssh: denial of service via sftp responses with unknown request ids
A flaw was found in libssh. A malicious SFTP server can send responses for unknown request IDs that libssh clients keep queued indefinitely, causing unbounded memory growth and client-side denial of service.

Vendor Advisory Vendor Advisory NVD

Vulnerability Analysis

CVE-2026-59848 is exploitable with network access, and does not require authorization privileges or user interaction. This vulnerability is considered to have a low attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality and integrity, and a small impact on availability.

Attack Vector:
NETWORK
Attack Complexity:
LOW
Privileges Required:
NONE
User Interaction:
NONE
Scope:
UNCHANGED
Confidentiality Impact:
NONE
Integrity Impact:
NONE
Availability Impact:
LOW

Timeline

Reported to Red Hat.

Made public. 83 days later.

Weakness Type

Allocation of Resources Without Limits or Throttling

The software allocates a reusable resource or group of resources on behalf of an actor without imposing any restrictions on the size or number of resources that can be allocated, in violation of the intended security policy for that actor.


Products Associated with CVE-2026-59848

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Red Hat Enterprise Linux (RHEL)
 
Red Hat Hummingbird
 

Affected Versions

Red Hat Enterprise Linux 10: Red Hat Hardened Images: Red Hat Enterprise Linux 8: Red Hat Enterprise Linux 9: