Vulnerability · Published Jun 10, 2026 · Assigned by EEF
CVE-2026-48858ftp client PASV response IP not validated against control peer, enabling SSRF and FTP bounce attacks
Medium 6.3
In plain English
A medium-severity server-side request forgery in OTP from Erlang. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.2% (higher than 14% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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 OTP 29.0.2, OTP 28.5.0.2 and OTP 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | erlang | no fix listed | DEBIAN-CVE-2026-48858 |
| Debian:13 | erlang | 1:27.3.4.1+dfsg-1+deb13u3 | DEBIAN-CVE-2026-48858 |
| Debian:14 | erlang | 1:29.0.2+dfsg-1 | DEBIAN-CVE-2026-48858 |
| Ubuntu:22.04:LTS | erlang | 1:24.2.1+dfsg-1ubuntu0.8 | USN-8901-1 |
| Ubuntu:22.04:LTS | erlang | 1:24.2.1+dfsg-1ubuntu0.8 | UBUNTU-CVE-2026-48858 |
| Ubuntu:24.04:LTS | erlang | 1:25.3.2.8+dfsg-1ubuntu4.8 | USN-8901-1 |
| Ubuntu:24.04:LTS | erlang | 1:25.3.2.8+dfsg-1ubuntu4.8 | UBUNTU-CVE-2026-48858 |
| Ubuntu:25.10 | erlang | no fix listed | UBUNTU-CVE-2026-48858 |
| Ubuntu:26.04:LTS | erlang | 1:27.3.4.6+dfsg-1ubuntu0.2 | UBUNTU-CVE-2026-48858 |
| Ubuntu:26.04:LTS | erlang | 1:27.3.4.6+dfsg-1ubuntu0.2 | USN-8901-1 |
Affected products (as reported)
Weakness: CWE-918 · 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
References
- https://github.com/erlang/otp/security/advisories/GHSA-24cv-hwgr-37fq vendor-advisory, related
- https://cna.erlef.org/cves/CVE-2026-48858.html related
- https://osv.dev/vulnerability/EEF-CVE-2026-48858 related
- https://www.erlang.org/doc/system/versions.html#order-of-versions x_version-scheme
- https://github.com/erlang/otp/commit/2691a806231ffd0490a8a9e20500dec0c7e73727 patch
- https://github.com/erlang/otp/commit/521bcfa24407ee8cb5614823cf905c37ea3aa605 patch