CVE-2025-32433
About
Erlang/OTP is a set of libraries for the Erlang programming language. Prior to versions OTP-27.3.3, OTP-26.2.5.11, and OTP-25.3.2.20, a SSH server may allow an attacker to perform unauthenticated remote code execution (RCE). By exploiting a flaw in SSH protocol message handling, a malicious actor could gain unauthorized access to affected systems and execute arbitrary commands without valid credentials. This issue is patched in versions OTP-27.3.3, OTP-26.2.5.11, and OTP-25.3.2.20. A temporary workaround involves disabling the SSH server or to prevent access via firewall rules.
Rainforest analyst review
The flaw is in the SSH server implementation shipped with Erlang/OTP's ssh library. The server mishandles SSH protocol messages, accepting and acting on certain connection-protocol messages before authentication has completed. An unauthenticated attacker who can open a TCP connection to the SSH port can drive the state machine into executing operations without ever presenting valid credentials, leading to remote code execution on the host running the Erlang SSH daemon, in many cases with the privileges of that service.
Erlang/OTP powers telecom infrastructure, messaging platforms, databases, and a range of embedded and networking products, and its SSH server is often used for device management, so the exposure reaches deep into systems that are not obviously Erlang applications, including Cisco and other vendors' gear. A CVSS 10 pre-auth RCE with a trivially reachable trigger meant public proof-of-concept code and scanning appeared almost immediately. Update to OTP-27.3.3, 26.2.5.11, or 25.3.2.20 or the vendor-specific fixed build; where patching lags, disable the Erlang SSH server or firewall the port off entirely, since any exposed instance should be considered a live target.
References
- https://github.com/erlang/otp/commit/0fcd9c56524b28615e8ece65fc0c3f66ef6e4c12
- https://github.com/erlang/otp/commit/6eef04130afc8b0ccb63c9a0d8650209cf54892f
- https://github.com/erlang/otp/commit/b1924d37fd83c070055beb115d5d6a6a9490b891
- https://github.com/erlang/otp/security/advisories/GHSA-37cp-fgq5-7wc2
- http://www.openwall.com/lists/oss-security/2025/04/16/2
- http://www.openwall.com/lists/oss-security/2025/04/18/1
- http://www.openwall.com/lists/oss-security/2025/04/18/2
- http://www.openwall.com/lists/oss-security/2025/04/18/6
- http://www.openwall.com/lists/oss-security/2025/04/19/1
- https://lists.debian.org/debian-lts-announce/2025/04/msg00028.html
- https://security.netapp.com/advisory/ntap-20250425-0001/
- https://github.com/ProDefense/CVE-2025-32433/blob/main/CVE-2025-32433.py
- https://sec.cloudapps.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-erlang-otp-ssh-xyZZy
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-32433
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Frequently asked questions
What is CVE-2025-32433?
Erlang/OTP is a set of libraries for the Erlang programming language. Prior to versions OTP-27.3.3, OTP-26.2.5.11, and OTP-25.3.2.20, a SSH server may allow an attacker to perform unauthenticated remote code execution (RCE). By exploiting a flaw in SSH protocol message handling, a malicious actor could gain unauthorized access to affected systems and execute arbitrary commands without valid credentials.
How severe is CVE-2025-32433?
CVE-2025-32433 carries a CVSS 3.1 base score of 10, rated critical. On the Rainforest Risk Index — which weighs the severity alongside how easy the flaw is to reach and how broad its impact is — it scores 100 out of 100, in the critical band.
How is CVE-2025-32433 exploited?
According to the CVSS vector (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H): attack vector Network, attack complexity Low, privileges required None, user interaction None. Impact on confidentiality High, integrity High and availability High.
Which products are affected by CVE-2025-32433?
Public advisories list the following as affected: cloud native broadband network gateway, confd basic, debian linux, enterprise nfv infrastructure software, erlang/otp, inode manager, +30. Check the references on this page for the exact versions each vendor confirms.
How do I fix CVE-2025-32433?
Apply the fix the vendor published — the references on this page link to the primary advisories and patches. When patching can't happen right away, reduce the exposure of the affected component and watch it for exploitation attempts. Rainforest customers see this vulnerability correlated to their own assets and prioritized by real exposure, not by score alone.
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