ftp client PASV response IP not validated against control peer, enabling SSRF and FTP bounce attacks

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Summary

CVECVE-2026-48858
StatePUBLISHED
AssignerEEF
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-06-10 16:17:11 UTC
Updated2026-06-11 19:27:00 UTC
DescriptionServer-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.

Risk And Classification

Primary CVSS: v4.0 6.3 MEDIUM from 6b3ad84c-e1a6-4bf7-a703-f496b71e49db

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

Problem Types: CWE-918 | CWE-918 CWE-918 Server-Side Request Forgery (SSRF)

VersionSourceTypeScoreSeverityVector
4.06b3ad84c-e1a6-4bf7-a703-f496b71e49dbSecondary6.3MEDIUMCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N/E:X/C...
4.0CNACVSS6.3MEDIUMCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N
3.1[email protected]Primary6.5MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

CVSS v4.0 Breakdown

Attack Vector
Network
Attack Complexity
Low
Attack Requirements
Present
Privileges Required
None
User Interaction
None
Confidentiality
Low
Integrity
Low
Availability
None
Sub Conf.
Low
Sub Integrity
Low
Sub Availability
None

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
Low
Availability
None

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

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Erlang Erlang/inets All All All All
Application Erlang Erlang/otp All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Erlang OTP affected 5.10.4 7.0 otp Not specified
CNA Erlang OTP affected 1.0 * otp Not specified
CNA Erlang OTP affected 17.4 * otp Not specified
CNA Erlang OTP affected be95772ee1fcfe71045ef070130bea7a910b81e3 * git Not specified

References

ReferenceSourceLinkTags
github.com/erlang/otp/security/advisories/GHSA-24cv-hwgr-37fq 6b3ad84c-e1a6-4bf7-a703-f496b71e49db github.com Mitigation, Vendor Advisory
osv.dev/vulnerability/EEF-CVE-2026-48858 6b3ad84c-e1a6-4bf7-a703-f496b71e49db osv.dev Mitigation, Third Party Advisory
www.erlang.org/doc/system/versions.html 6b3ad84c-e1a6-4bf7-a703-f496b71e49db www.erlang.org Product
cna.erlef.org/cves/CVE-2026-48858.html 6b3ad84c-e1a6-4bf7-a703-f496b71e49db cna.erlef.org Mitigation, Third Party Advisory
github.com/erlang/otp/commit/521bcfa24407ee8cb5614823cf905c37ea3aa605 6b3ad84c-e1a6-4bf7-a703-f496b71e49db github.com Patch
github.com/erlang/otp/commit/2691a806231ffd0490a8a9e20500dec0c7e73727 6b3ad84c-e1a6-4bf7-a703-f496b71e49db github.com Patch
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: Jonatan Männchen / EEF (en)

CNA: Jonatan Männchen / EEF (en)

CNA: Ingela Anderton Andin (en)

Additional Advisory Data

Workarounds

CNA: 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.

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