FileZilla Server 1.10.3 crashes when RETR’ing a specific JPEG file (20.S25-041119.jpg)

[Daniel]

Environment
FileZilla Server version: 1.10.3 (latest stable)
OS: Windows Server 2019 / Windows 10
Connection: Explicit FTP over TLS enabled; Passive Mode using EPSV (and PASV fallback tested)

Clients Tested
n8n FTP Node (basic-ftp library) — download of this file triggers server crash
curl with --disable-epsv — download still crashes the server
Windows built-in ftp client (with passive then get) — successfully retrieves the file

Descrition
When attempting to download (RETR) the file 20.S25-041119.jpg, the FileZilla Server process terminates unexpectedly (service restarts) within the data transfer phase. No “226 Transfer complete” reply is ever sent. The same transfer of other files (including other JPEGs) succeeds reliably. Changing the filename or extension to .txt does not avoid the crash; however, compressing the file into a ZIP container makes the transfer succeed.

Relevant Log Excerpt
…
2025-05-09T11:46:32.454Z >> RETR /Zoder/Ausgang/POD/20.S25-041119.jpg
2025-05-09T11:46:32.454Z << 150 Starting data transfer.
no subsequent “226 Transfer complete”
2025-05-09T11:53:37.570Z == ===== FileZilla Server 1.10.3 new logging started =====
…

Notes & Hypothesis
The crash is deterministic for this exact byte-pattern; renaming the file does not help.

Zipping the file (changing its binary stream) bypasses the bug, pointing to a corner-case in the VFS streaming code.

[Daniel]

JPG-File as .TXT

[Daniel]

the jpg that crashes the server

[Tim Kosse]

Please attach the complete log of the transfer as well as the generated crashdumps. They are located under C:\Windows\system32\config\systemprofile\AppData\Local\CrashDumps