CVE-2020-10188

💻 Affected Systems

📦 What is this software?

⚠️ Risk & Real-World Impact

🎯 Exploit Status

Buffer overflow in netclear/nextitem functions allows straightforward exploitation. Public references demonstrate the vulnerability.

🔍 How to Verify

Check netkit-telnet version: dpkg -l | grep netkit-telnet or rpm -qa | grep netkit-telnet. If version is 0.17 or earlier, system is vulnerable.

dpkg -l | grep netkit-telnet  # Debian/Ubuntu
rpm -qa | grep netkit-telnet  # RHEL/Fedora

Verify updated version: dpkg -l | grep netkit-telnet should show version >0.17. Test telnet service functionality after update.

📡 Detection & Monitoring

source="telnet.log" AND ("buffer overflow" OR "segmentation fault" OR "urgent data")

🔗 References

• https://appgateresearch.blogspot.com/2020/02/bravestarr-fedora-31-netkit-telnetd_28.html Third Party Advisory
• https://github.com/krb5/krb5-appl/blob/d00cd671dfe945791b33d4f1f6a5c57ae1667ef8/telnet/telnetd/utility.c#L205-L216 Patch,Third Party Advisory
• https://lists.debian.org/debian-lts-announce/2020/05/msg00012.html Mailing List,Third Party Advisory
• https://lists.debian.org/debian-lts-announce/2020/08/msg00038.html Mailing List,Third Party Advisory
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/7FMTRRQTYKWZD2GMXX3GLZV46OLPCLVK/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HLU6FL24BSQQEB2SJC26NLJ2MANQDA7M/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/K3VJ6V2Z3JRNJOBVHSOPMAC76PSSKG6A/
• https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-telnetd-EFJrEzPx Third Party Advisory
• https://www.arista.com/en/support/advisories-notices/security-advisories/10702-security-advisory-48 Third Party Advisory
• https://www.oracle.com/security-alerts/cpuApr2021.html Patch,Third Party Advisory
• http://www.openwall.com/lists/oss-security/2026/01/20/8
• https://appgateresearch.blogspot.com/2020/02/bravestarr-fedora-31-netkit-telnetd_28.html Third Party Advisory
• https://github.com/krb5/krb5-appl/blob/d00cd671dfe945791b33d4f1f6a5c57ae1667ef8/telnet/telnetd/utility.c#L205-L216 Patch,Third Party Advisory
• https://lists.debian.org/debian-lts-announce/2020/05/msg00012.html Mailing List,Third Party Advisory
• https://lists.debian.org/debian-lts-announce/2020/08/msg00038.html Mailing List,Third Party Advisory
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/7FMTRRQTYKWZD2GMXX3GLZV46OLPCLVK/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HLU6FL24BSQQEB2SJC26NLJ2MANQDA7M/
• https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/K3VJ6V2Z3JRNJOBVHSOPMAC76PSSKG6A/
• https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-telnetd-EFJrEzPx Third Party Advisory
• https://www.arista.com/en/support/advisories-notices/security-advisories/10702-security-advisory-48 Third Party Advisory
• https://www.oracle.com/security-alerts/cpuApr2021.html Patch,Third Party Advisory