USN-4434-1: LibVNCServer vulnerabilities

First published: Thu Jul 23 2020(Updated: )

Ramin Farajpour Cami discovered that LibVNCServer incorrectly handled certain malformed unix socket names. A remote attacker could exploit this with a crafted socket name, leading to a denial of service, or possibly execute arbitrary code. (CVE-2019-20839) It was discovered that LibVNCServer did not properly access byte-aligned data. A remote attacker could possibly use this issue to cause LibVNCServer to crash, resulting in a denial of service. This issue only affected Ubuntu 18.04 LTS and Ubuntu 16.04 LTS. (CVE-2019-20840) Christian Beier discovered that LibVNCServer incorrectly handled anonymous TLS connections. A remote attacker could possibly use this issue to cause LibVNCServer to crash, resulting in a denial of service. This issue only affected Ubuntu 20.04 LTS. (CVE-2020-14396) It was discovered that LibVNCServer incorrectly handled region clipping. A remote attacker could possibly use this issue to cause LibVNCServer to crash, resulting in a denial of service. (CVE-2020-14397) It was discovered that LibVNCServer did not properly reset incorrectly terminated TCP connections. A remote attacker could possibly use this issue to cause an infinite loop, resulting in a denial of service. (CVE-2020-14398) It was discovered that LibVNCServer did not properly access byte-aligned data. A remote attacker could possibly use this issue to cause LibVNCServer to crash, resulting in a denial of service. (CVE-2020-14399, CVE-2020-14400) It was discovered that LibVNCServer incorrectly handled screen scaling on the server side. A remote attacker could use this issue to cause LibVNCServer to crash, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2020-14401) It was discovered that LibVNCServer incorrectly handled encodings. A remote attacker could use this issue to cause LibVNCServer to crash, resulting in a denial of service, or possibly execute arbitrary code. (CVE-2020-14402, CVE-2020-14403, CVE-2020-14404) It was discovered that LibVNCServer incorrectly handled TextChat messages. A remote attacker could possibly use this issue to cause LibVNCServer to crash, resulting in a denial of service. (CVE-2020-14405)

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