USN-8699-1: libssh vulnerabilities

USN-8699-1: libssh vulnerabilities

https://ubuntu.com/security/notices/rss.xml / Mon, 08/31/2026 - 16:29
It was discovered that libssh had a stack buffer overflow in its SFTP server when constructing directory listing entries for long filenames. An attacker could possibly use this issue to cause libssh to crash or execute arbitrary code. This issue only affected Ubuntu 26.04 LTS. (CVE-2026-15370) It was discovered that libssh did not correctly handle SSH channel open messages advertising a zero maximum packet size. An authenticated remote attacker could possibly use this issue to cause libssh to consume excessive CPU resources, leading to a denial of service. (CVE-2026-59843) It was discovered that libssh did not correctly limit SFTP read request lengths in its server implementation. An authenticated remote attacker could possibly use this issue to cause libssh to allocate excessive memory, leading to a denial of service. This issue only affected Ubuntu 26.04 LTS. (CVE-2026-59844) It was discovered that libssh did not correctly handle ProxyCommand fork() failures. A local attacker could possibly use this issue to cause a denial of service. (CVE-2026-59845) It was discovered that libssh did not correctly sanitize shell metacharacters when expanding usernames in ProxyCommand strings. An attacker could possibly use this issue to obtain sensitive information. (CVE-2026-59846) It was discovered that libssh had incorrect AES-GCM tag verification when built with the OpenSSL backend. A machine-in-the-middle attacker could possibly use this issue to modify encrypted traffic without detection. (CVE-2026-59847) It was discovered that libssh did not correctly handle SFTP server responses for unknown request IDs. An attacker could possibly use this issue to cause libssh to use excessive memory, leading to a denial of service. (CVE-2026-59848) It was discovered that libssh had logic errors in certificate-based authentication that could cause clients to loop indefinitely when certificates were rejected. An attacker could possibly use this issue to cause a denial of service. This issue only affected Ubuntu 26.04 LTS. (CVE-2026-59849) It was discovered that libssh could invoke data callbacks on channels after they had been closed. An attacker could possibly use this issue to cause libssh to crash or execute arbitrary code. (CVE-2026-59850)

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Kenya Education Network CERT(KENET-CERT) is a Cybersecurity Emergency Response Team and Co-ordination Center operated by the National Research and Education Network of Kenya. KENET-CERT coordination center promotes awareness on cybersecurity incidences as well as coordinates and assists member institutions in responding effectively to cyber security threats and incidences. KENET-CERT works closely with Kenya's National CIRT coordination center (CIRT/CC) as a sector CIRT for the academic institutions. KENET promotes use of ICT in Teaching, Learning and Research in Higher Education Institutions in Kenya. KENET aims to interconnect all the Universities, Tertiary and Research Institutions in Kenya by setting up a cost effective and sustainable private network with high speed access to the global Internet. KENET also facilitates electronic communication among students and faculties in member institutions, share learning and teaching resources by collaboration in Research and Development of Educational content.