USN-8799-1: libssh2 vulnerabilities
Ubuntu's USN-8799-1 fixes libssh2 bugs that a malicious SSH server can use for denial of service or possible code execution.
Ubuntu Security Notice USN-8799-1 covers vulnerabilities in libssh2. CVE-2026-58050 is incorrect handling of publickey subsystem attributes, and CVE-2026-58051 is use of publickey list entries before they are initialized. A remote attacker who controls a malicious SSH server could cause a denial of service or possibly execute arbitrary code. The notice also says certain SFTP server responses can crash libssh2 or possibly lead to code execution. No exploitation in the wild is reported.
- CVE-2026-58050: unsafe handling of publickey subsystem attributes.
- CVE-2026-58051: publickey list entries used before initialization.
- Attacker must control the SSH server the libssh2 client connects to.
- SFTP response handling can also crash the library; no in-the-wild exploitation stated.
Vulnerabilities mentioned
All| CVE | Vulnerability | CVSS | EPSS | Signals | Published |
|---|---|---|---|---|---|
CVE-2026-58050+1 related CVE | libssh2 through 1.11.1 reads an attacker-controlled 32-bit attribute count from a publickey-subsystem response and uses it in the allocation num_attrs *… | 8.3 | <1% |
From the original article
It was discovered that libssh2 incorrectly handled certain publickey subsystem attributes. A remote attacker controlling a malicious SSH server could use this issue to cause a denial of service or possibly execute arbitrary code. (CVE-2026-58050) It was discovered that libssh2 did not properly initialize publickey list entries before parsing.
ubuntu.com
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