Description
Erlang/OTP is a set of libraries for the Erlang programming language. In versions prior to OTP-27.3.4 (for OTP-27), OTP-26.2.5.12 (for OTP-26), and OTP-25.3.2.21 (for OTP-25), Erlang/OTP SSH fails to enforce strict KEX handshake hardening measures by allowing optional messages to be exchanged. This allows a Man-in-the-Middle attacker to inject these messages in a connection during the handshake. This issue has been patched in versions OTP-27.3.4 (for OTP-27), OTP-26.2.5.12 (for OTP-26), and OTP-25.3.2.21 (for OTP-25).
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| erlang | otp | >= OTP 27.0, < OTP 27.3.4, >= OTP 26.2.1, < OTP 26.2.5.12, < OTP 25.3.2.21 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | erlang | 1:27.3.4+dfsg-1 | — |
| Debian 13 | erlang | 1:27.3.4+dfsg-1 | — |
| Debian 12 | erlang | 1:25.2.3+dfsg-1+deb12u2 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 25.10 | erlang | 1:27.3.4.1+dfsg-1 | — |
| Ubuntu 24.04 LTS | erlang | 1:25.3.2.8+dfsg-1ubuntu4.4 | USN-7656-1 |
| Ubuntu 22.04 LTS | erlang | 1:24.2.1+dfsg-1ubuntu0.5 | USN-7656-1 |
Show 4 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 20.04 LTS | erlang | No fix yet | — |
| Ubuntu Pro 18.04 LTS | erlang | No fix yet | — |
| Ubuntu Pro 16.04 LTS | erlang | No fix yet | — |
| Ubuntu Pro 14.04 LTS | erlang | No fix yet | — |
Alpine
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine v3.21 | erlang | 26.2.5.12-r0 | — |
Azure Linux
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Azure Linux 3 | erlang | 26.2.5.12-1 | — |
| Azure Linux 2 (CBL-Mariner) | erlang | 25.3.2.21-1 | — |
Advisories 2
- USN-7656-1 erlang vulnerabilities Ubuntu Security Notices (USN) · Apr 27, 2026
- WID-SEC-2025-0989 Erlang/OTP: Schwachstelle ermöglicht Umgehen von Sicherheitsvorkehrungen BSI CERT-Bund (WID) · Jul 21, 2025
References
- https://github.com/erlang/otp/security/advisories/GHSA-934x-xq38-hhqf
- https://github.com/erlang/otp/commit/e4b56a9f4a511aa9990dd86c16c61439c828df83
- https://github.com/erlang/otp/releases/tag/OTP-25.3.2.21
- https://github.com/erlang/otp/releases/tag/OTP-26.2.5.12
- https://github.com/erlang/otp/releases/tag/OTP-27.3.4