SEPTEMBER 7, 2026
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Case File

CVE-2026-63091

MEDIUM · CVSS 6.5 EPSS 0.29% Public Exploit

Source: NVD + CISA KEV + EPSS · Published 2026-07-20 · Last synced 2026-08-19

CyberRota Analysis

AI-Generated

ProFTPD versions prior to 1.3.9c and 1.3.10rc3 are vulnerable to a signed integer overflow in the mod_sftp module, allowing authenticated low-privilege attackers to bypass Address Space Layout Randomization (ASLR). By sending a specially crafted file size value, attackers can manipulate memory, potentially leading to the disclosure of sensitive information such as libc and libcrypto pointers, which can facilitate further exploitation. Organizations using affected versions of ProFTPD should prioritize patching to mitigate the risk of memory corruption vulnerabilities.

Public Exploit Signal

A public exploit, PoC, GitHub repository or Metasploit reference was detected for this CVE.

Detected Signals
exploit

Note: these links are listed for security research and verification purposes only.

CVE
CVE-2026-63091
Severity
MEDIUM
CVSS
6.5
EPSS
0.29%

Original NVD Description

ProFTPD before 1.3.9c and 1.3.10rc3 contains a signed integer overflow vulnerability in the mod_sftp module's SCP size-record parser that allows authenticated low-privilege attackers to bypass ASLR by sending a crafted file size value of UINT64_MAX, which results in a negative off_t value. Attackers can exploit the subsequent conversion to uint32_t, causing an approximately 4 GB requested read length and forcing the server to read beyond the end of the SSH channel data and write overread process memory into the uploaded file. In tested configurations, the disclosed data contains libc, libcrypto, and PIE pointers sufficient to derive their randomized base addresses, thereby bypassing ASLR and enabling reliable exploitation of memory corruption vulnerabilities in the same process.

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