PT-2026-61612 · Proftpd · Proftpd

CVE-2026-63091 · Published 2026-07-20 · Updated 2026-07-20

Mitre

CVSS v3.1

6.5

Medium

Base vector

AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

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.

Fix

Integer Overflow

Buffer Over-read

Weakness Enumeration

CWE-190

CWE-126

Related Identifiers

CVE-2026-63091

Affected Products

Proftpd

References · 7

• https://github.com/proftpd/proftpd/commit/b9b7dde1bcd74bc23366484d53856b67b8d6d95e · Patch
• https://nvd.nist.gov/vuln/detail/CVE-2026-63091 · Security Note
• https://github.com/proftpd/proftpd/releases/tag/v1.3.10rc3-3 · Note
• https://github.com/proftpd/proftpd/releases/tag/v1.3.9c · Note
• https://github.com/proftpd/proftpd/pull/2201 · Note
• https://github.com/proftpd/proftpd/blob/master/RELEASE_NOTES · Note
• https://vulncheck.com/advisories/proftpd-mod-sftp-signed-integer-overflow-via-scp-size-record-parser · Note