Server-Side Request Forgery (SSRF) vulnerability in Erlang/OTP ftp (ftp_internal module) allows FTP bounce attacks and SSRF via an unvalidated PASV response IP address.

The ftp_internal:handle_ctrl_result/2 PASV handler (mode=passive, ipfamily=inet, ftp_extension=false) extracts the IP address from the server's 227 response and passes it directly to gen_tcp:connect/4 without validating it against the control connection peer address. The adjacent EPSV handlers correctly call peername(CSock) to derive the IP from the control connection, but the PASV handler does not. A malicious or compromised FTP server can redirect the client's data connection to an arbitrary internal host and port. On read operations (ftp:ls/1,2, ftp:nlist/1,2, ftp:recv/2,3), data from the redirected target is returned to the caller. On write operations (ftp:send/2,3, ftp:append/2,3), file content is sent to the redirected target. This enables SSRF against internal hosts, cloud metadata endpoints, and FTP bounce attacks against third-party hosts.

The vulnerable path is the default configuration (mode=passive, ipfamily=inet, ftp_extension=false). RFC 2577 section 3 explicitly recommends validating the PASV response IP against the control connection peer.

The ftp application is deprecated and scheduled for removal in OTP-30.

This vulnerability is associated with program files lib/inets/src/ftp/ftp_internal.erl (inets 5.10.4 through 6.5, OTP 17.4 through 20.3) and lib/ftp/src/ftp_internal.erl (ftp 1.0 and later, OTP 21.0 and later).

This issue affects OTP from OTP 17.4 before 29.0.2, 28.5.0.2 and 27.3.4.13 corresponding to inets from 5.10.4 before 7.0 and ftp from 1.0 before 1.2.6, 1.2.4.1 and 1.2.3.1.

Project Subscriptions

Vendors Products
Erlang\/otp Subscribe
Advisories

No advisories yet.

Fixes

Solution

No solution given by the vendor.


Workaround

Pass {ftp_extension, true} to ftp:open/2 to use EPSV instead of PASV. Alternatively, pass {mode, active} to use active mode, or pass {ipfamily, inet6} to force IPv6, both of which bypass the vulnerable PASV path.

History

Wed, 10 Jun 2026 17:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Wed, 10 Jun 2026 16:00:00 +0000

Type Values Removed Values Added
Description Server-Side Request Forgery (SSRF) vulnerability in Erlang/OTP ftp (ftp_internal module) allows FTP bounce attacks and SSRF via an unvalidated PASV response IP address. The ftp_internal:handle_ctrl_result/2 PASV handler (mode=passive, ipfamily=inet, ftp_extension=false) extracts the IP address from the server's 227 response and passes it directly to gen_tcp:connect/4 without validating it against the control connection peer address. The adjacent EPSV handlers correctly call peername(CSock) to derive the IP from the control connection, but the PASV handler does not. A malicious or compromised FTP server can redirect the client's data connection to an arbitrary internal host and port. On read operations (ftp:ls/1,2, ftp:nlist/1,2, ftp:recv/2,3), data from the redirected target is returned to the caller. On write operations (ftp:send/2,3, ftp:append/2,3), file content is sent to the redirected target. This enables SSRF against internal hosts, cloud metadata endpoints, and FTP bounce attacks against third-party hosts. The vulnerable path is the default configuration (mode=passive, ipfamily=inet, ftp_extension=false). RFC 2577 section 3 explicitly recommends validating the PASV response IP against the control connection peer. The ftp application is deprecated and scheduled for removal in OTP-30. This vulnerability is associated with program files lib/inets/src/ftp/ftp_internal.erl (inets 5.10.4 through 6.5, OTP 17.4 through 20.3) and lib/ftp/src/ftp_internal.erl (ftp 1.0 and later, OTP 21.0 and later). This issue affects OTP from OTP 17.4 before 29.0.2, 28.5.0.2 and 27.3.4.13 corresponding to inets from 5.10.4 before 7.0 and ftp from 1.0 before 1.2.6, 1.2.4.1 and 1.2.3.1.
Title ftp client PASV response IP not validated against control peer, enabling SSRF and FTP bounce attacks
First Time appeared Erlang
Erlang erlang\/otp
Weaknesses CWE-918
CPEs cpe:2.3:a:erlang:erlang\/otp:*:*:*:*:*:*:*:*
Vendors & Products Erlang
Erlang erlang\/otp
References
Metrics cvssV4_0

{'score': 6.3, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N'}


Projects

Sign in to view the affected projects.

cve-icon MITRE

Status: PUBLISHED

Assigner: EEF

Published:

Updated: 2026-06-10T16:21:08.893Z

Reserved: 2026-05-25T20:44:10.697Z

Link: CVE-2026-48858

cve-icon Vulnrichment

Updated: 2026-06-10T16:21:01.387Z

cve-icon NVD

Status : Received

Published: 2026-06-10T16:17:11.077

Modified: 2026-06-10T16:17:11.077

Link: CVE-2026-48858

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-06-10T17:30:36Z

Weaknesses