CVE-2026-116844

Fclairamb ftpserverlib through 0.32.4 contains a cleartext transmission vulnerability because TransferOpen checks only the transferTLS flag set by PROT, not whether the prepared data connection uses TLS. When a client sends PROT P after PASV or PORT, file contents and directory listings cross the network unencrypted, even with mandatory encryption, letting on-path attackers read or modify them.

CVSS 4.0

6.3CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N

CVSS 3.1

4.8CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N

CWE

CWE-319

Published

2026-10-27

Modified

2026-10-27

Record from

the NVD, synced 2026-10-27

References

• https://github.com/fclairamb/ftpserverlib/blob/v0.32.4/client_handler.go#L720
• https://github.com/fclairamb/ftpserverlib/blob/v0.32.4/handle_misc.go#L29-L31
• https://github.com/fclairamb/ftpserverlib/pull/685
• https://www.vulncheck.com/advisories/fclairamb-ftpserverlib-through-0.32.4-cleartext-ftpes-data-transfer-via-prot-p

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