Client memory exhaustion via queued unknown responses
Published Jul 21, 2026 · Updated Jul 21, 2026
Unbounded resource allocation in libssh SFTP clients allows remote attackers controlling an SFTP server to exhaust client memory. In sftp_get_message() in src/sftp_common.c, the client accepts responses for request IDs it never issued and retains them in its message queue. Exploitation requires a client application to connect to an attacker-controlled SFTP server, which can grow the queue without limit and interrupt the client through memory exhaustion.
Summary
What happened
Unbounded resource allocation in libssh SFTP clients allows remote attackers controlling an SFTP server to exhaust client memory. In sftp_get_message() in src/sftp_common.c, the client accepts responses for request IDs it never issued and retains them in its message queue. Exploitation requires a client application to connect to an attacker-controlled SFTP server, which can grow the queue without limit and interrupt the client through memory exhaustion.
The record
- CVE
- CVE-2026-59848
- Published
- Jul 21, 2026
- Updated
- Jul 21, 2026
- Vendor
- 389 Directory Server
- Product
- Red Hat Enterprise Linux 10
- Classifications
- CWE-770, T1499.003
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jul 21, 2026CVE publishedPublication date reported by the CVE source.
- Jul 21, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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