libssh SFTP Excessive Memory Allocation via SSH_FXP_READ (CVE-2026-59844)
CVE-2026-59844 Published on July 21, 2026
Libssh: libssh: denial of service via oversized sftp read length
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.
Vulnerability Analysis
CVE-2026-59844 is exploitable with network access, and requires small amount of user privileges. 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 high impact on availability.
Timeline
Reported to Red Hat.
Made public. 83 days later.
Weakness Type
What is a Stack Exhaustion Vulnerability?
The product allocates memory based on an untrusted, large size value, but it does not ensure that the size is within expected limits, allowing arbitrary amounts of memory to be allocated.
CVE-2026-59844 has been classified to as a Stack Exhaustion vulnerability or weakness.
Products Associated with CVE-2026-59844
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