critical
CVE-2020-10188
telnet-server: no bounds checks in nextitem() function allows to remotely execute arbitrary code
In the Trivy database since at least 24 Oct 2026, 07:11 UTCWhen it arrived before that build is not recorded.
Severity by source
NVD9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Red Hat9.8CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Trivy's own label is CRITICAL. Rated critical by NVD, Photon OS. Rated lower by Red Hat (high), Amazon (high), Oracle (high), Ubuntu (medium).
Description
utility.c in telnetd in netkit telnet through 0.17 allows remote attackers to execute arbitrary code via short writes or urgent data, because of a buffer overflow involving the netclear and nextitem functions.
Affected packages and fixed versions
| Source | Package | Fixed in |
|---|---|---|
| Photon OS 4.0 | netkit-telnet, netkit-telnet-server | 0.17-5.ph4 |
| Photon OS 5.0 | netkit-telnet, netkit-telnet-server | 0.17-8.ph5 |
| amazon linux 1 | telnet, telnet-debuginfo, telnet-server | 1:0.17-49.9.amzn1 |
| amazon linux 2 | telnet, telnet-debuginfo, telnet-server | 1:0.17-65.amzn2 |
| debian 10 | inetutils | 2:1.9.4-7+deb10u1 |
| debian 11 | inetutils, netkit-telnet, netkit-telnet-ssl | 2:1.9.4-12 and 2 more |
| debian 12 | inetutils, netkit-telnet-ssl | 2:1.9.4-12 and 1 more |
| debian 13 | inetutils, netkit-telnet-ssl | 2:1.9.4-12 and 1 more |
| debian 14 | inetutils, netkit-telnet-ssl | 2:1.9.4-12 and 1 more |
| debian 8 | inetutils | 2:1.9.2.39.3a460-3+deb8u1 |
| debian 9 | inetutils | 2:1.9.4-2+deb9u1 |
| echo | inetutils, netkit-telnet-ssl | 2:1.9.4-12 and 1 more |
Show all 37 entries from 20 sources
| Source | Package | Fixed in |
|---|---|---|
| Photon OS 4.0 | netkit-telnet | 0.17-5.ph4 |
| Photon OS 4.0 | netkit-telnet-server | 0.17-5.ph4 |
| Photon OS 5.0 | netkit-telnet | 0.17-8.ph5 |
| Photon OS 5.0 | netkit-telnet-server | 0.17-8.ph5 |
| amazon linux 1 | telnet | 1:0.17-49.9.amzn1 |
| amazon linux 1 | telnet-debuginfo | 1:0.17-49.9.amzn1 |
| amazon linux 1 | telnet-server | 1:0.17-49.9.amzn1 |
| amazon linux 2 | telnet | 1:0.17-65.amzn2 |
| amazon linux 2 | telnet-debuginfo | 1:0.17-65.amzn2 |
| amazon linux 2 | telnet-server | 1:0.17-65.amzn2 |
| debian 10 | inetutils | 2:1.9.4-7+deb10u1 |
| debian 11 | inetutils | 2:1.9.4-12 |
| debian 11 | netkit-telnet | 0.17-18woody2 |
| debian 11 | netkit-telnet-ssl | 0.17.17+0.1-2woody3 |
| debian 12 | inetutils | 2:1.9.4-12 |
| debian 12 | netkit-telnet-ssl | 0.17.17+0.1-2woody3 |
| debian 13 | inetutils | 2:1.9.4-12 |
| debian 13 | netkit-telnet-ssl | 0.17.17+0.1-2woody3 |
| debian 14 | inetutils | 2:1.9.4-12 |
| debian 14 | netkit-telnet-ssl | 0.17.17+0.1-2woody3 |
| debian 8 | inetutils | 2:1.9.2.39.3a460-3+deb8u1 |
| debian 9 | inetutils | 2:1.9.4-2+deb9u1 |
| echo | inetutils | 2:1.9.4-12 |
| echo | netkit-telnet-ssl | 0.17.17+0.1-2woody3 |
| Oracle Linux 6 | krb5-appl-clients | 1.0.1-10.el6_10 |
| Oracle Linux 6 | krb5-appl-servers | 1.0.1-10.el6_10 |
| Oracle Linux 6 | telnet | 1:0.17-49.el6_10 |
| Oracle Linux 6 | telnet-server | 1:0.17-49.el6_10 |
| Oracle Linux 7 | telnet | 1:0.17-65.el7_8 |
| Oracle Linux 7 | telnet-server | 1:0.17-65.el7_8 |
| Oracle Linux 8 | telnet | 1:0.17-73.el8_1.1 |
| Oracle Linux 8 | telnet-server | 1:0.17-73.el8_1.1 |
| ubuntu 16.04-ESM | inetutils | 2:1.9.4-1ubuntu0.1~esm1 |
| ubuntu 18.04 | inetutils | 2:1.9.4-3ubuntu0.1 |
| ubuntu 18.04-ESM | inetutils | 2:1.9.4-3ubuntu0.1 |
| ubuntu 20.04 | inetutils | 2:1.9.4-11ubuntu0.1 |
| ubuntu 20.04-ESM | inetutils | 2:1.9.4-11ubuntu0.1 |
References
- http://www.openwall.com/lists/oss-security/2026/01/20/8
- https://access.redhat.com/security/cve/CVE-2020-10188
- https://appgateresearch.blogspot.com/2020/02/bravestarr-fedora-31-netkit-telnetd_28.html
- https://github.com/krb5/krb5-appl/blob/d00cd671dfe945791b33d4f1f6a5c57ae1667ef8/telnet/telnetd/utility.c#L205-L216
- https://linux.oracle.com/cve/CVE-2020-10188.html
- https://linux.oracle.com/errata/ELSA-2020-1349.html
- https://lists.debian.org/debian-lts-announce/2020/05/msg00012.html
- https://lists.debian.org/debian-lts-announce/2020/08/msg00038.html
All 19 references
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/7FMTRRQTYKWZD2GMXX3GLZV46OLPCLVK/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/HLU6FL24BSQQEB2SJC26NLJ2MANQDA7M/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/K3VJ6V2Z3JRNJOBVHSOPMAC76PSSKG6A/
- https://nvd.nist.gov/vuln/detail/CVE-2020-10188
- https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-telnetd-EFJrEzPx
- https://ubuntu.com/security/notices/USN-5048-1
- https://ubuntu.com/security/notices/USN-5048-2
- https://ubuntu.com/security/notices/USN-7781-1
- https://www.arista.com/en/support/advisories-notices/security-advisories/10702-security-advisory-48
- https://www.cve.org/CVERecord?id=CVE-2020-10188
- https://www.oracle.com/security-alerts/cpuApr2021.html