Erlang/OTP SSH Vulnerable to Pre-Authentication RCE
Affects the Erlang/OTP SSH server from OTP 17.0 onward, per the advisory. Fixed in OTP-27.3.3, OTP-26.2.5.11, and OTP-25.3.2.20.
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Listed in CISA KEV
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Actively exploited
- Fix
- Fixed in OTP-27.3.3, OTP-26.2.5.11, OTP-25.3.2.20
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
Erlang/OTP, the libraries used to build Erlang applications, is affected when its built-in SSH server is running. An attacker who can reach that server could exploit a flaw in how it handles SSH messages to run arbitrary commands on the system without logging in.
Summarized by anthropic/claude-haiku-5.5. Verify details against the original sources.
Read the original description
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.
Timeline
- CVE published
- Added to CISA KEV
CISA has evidence of exploitation in the wild
- CISA remediation deadline
Due date for US federal agencies to patch
- Record last updated
- EPSS reached 10%
FIRST estimates at least a 10% chance of exploitation in the next 30 days
Affected versions
- erlang otp
From OTP-27.0-rc1 · fixed in OTP-27.3.3; From OTP-26.0-rc1 · fixed in OTP-26.2.5.11; fixed in OTP-25.3.2.20
References 4
GitHub · erlang/otp
Questions about CVE-2025-32433
What does this mean?
The flaw lets an unauthenticated remote attacker run arbitrary commands on the host without valid credentials. The advisory also says it may cause denial of service or allow manipulation of sensitive data.Source: github.com
Am I affected, and how do I check?
The advisory says all users running the Erlang/OTP SSH server are impacted, starting from OTP 17.0. To check a system, confirm whether the SSH server is running and which OTP release is installed.Source: github.com
What should I do about it?
Update to OTP-27.3.3 for OTP-27, OTP-26.2.5.11 for OTP-26, or OTP-25.3.2.20 for OTP-25. Until the upgrade, disable the SSH server or block access to it with firewall rules.Source: github.com
Is it being exploited?
Yes. CISA added it to its Known Exploited Vulnerabilities catalog on 2025-06-09, which means it has evidence of attacks. No public exploit code is tracked.Source: cisa.gov, cve.now feed data