CVE-2026-63090: ProFTPD mod_sftp Heap Buffer Overflow via SFTP Packet Reassembly
ProFTPD before 1.3.9c and 1.3.10rc3 contains a heap-based buffer overflow vulnerability in the modsftp module that allows authenticated low-privilege attackers to achieve arbitrary code execution by sending crafted SFTP packet fragments exceeding the 16 KB reassembly buffer in the fxp.c component. Attackers can supply oversized fragments to trigger an incorrectly conditioned reallocation, corrupt pool freelist metadata, overwrite the rootfs BSS global pointer to reference a fake filesystem struct, and redirect prfsiostat() to system() via a crafted RENAME request.
Affected Software
Event History
Frequently Asked Questions
What is the severity of CVE-2026-63090?
CVE-2026-63090 has a high severity rating of 8.8.
How do I fix CVE-2026-63090?
To fix CVE-2026-63090, upgrade to ProFTPD version 1.3.9c or 1.3.10rc3 or later.
What type of vulnerability is CVE-2026-63090?
CVE-2026-63090 is a heap-based buffer overflow vulnerability in the ProFTPD mod_sftp module.
Who is affected by CVE-2026-63090?
Authenticated low-privilege attackers can exploit CVE-2026-63090 to achieve arbitrary code execution.
What can attackers achieve by exploiting CVE-2026-63090?
By exploiting CVE-2026-63090, attackers can gain arbitrary code execution on the affected ProFTPD servers.