CVE-2020-10188
Criticalutility.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.
Published Jan 19, 2022 · Updated Aug 5, 2026 · Also known as DEBIAN-CVE-2020-10188, DLA-2176-1, DLA-2341-1, SUSE-SU-2020:1533-1, TR-22-0062, UBUNTU-CVE-2020-10188, USN-5048-1, USN-5048-2
Key Facts
Patch immediately- CVE-2020-10188 is a critical-severity vulnerability (CVSS 9.8 v3.1) affecting Netkit Telnet (Netkit Telnet Project), Communications Performance Intelligence Center (Oracle), Eos (Arista) and 22 more products.
- It is not listed in any known-exploited vulnerabilities catalog. No public exploit code is known.
- EPSS estimates a 74% probability of exploitation in the next 30 days.
- Fixed versions are available, including Eos 4.20.15, inetutils 2:1.9.2-1ubuntu0.1~esm2, inetutils 2:1.9.2.39.3a460-3+deb8u1.
- Brandefense priority: patch immediately, because it is very likely to be exploited soon.
CVSS v3.1
9.8
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS (30-day exploit likelihood)
74%
Higher than 99.4% of all scored CVEs
Exploited in the wild
No known
Not in a known-exploited catalog
Public exploit code
None known
Get the full CVE-2020-10188 brief as a PDF
Every affected product and fixed release, exploitation status and a first 24 hours response checklist, emailed within minutes.
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 Products
498 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| Netkit TelnetNetkit Telnet Project | See advisory | 0.17 |
| Communications Performance Intelligence CenterOracle | 10.4.0.2 | n/a |
| EosArista | 4.24.0f | 4.20.15 |
| Debian LinuxDebian | 8.0, 9.0 | n/a |
| FedoraFedoraproject | 30, 31, 32 | n/a |
Patched Releases
Eos
4.20.15
inetutils
2:1.9.2-1ubuntu0.1~esm2, 2:1.9.2.39.3a460-3+deb8u1, 2:1.9.4-11ubuntu0.1, 2:1.9.4-12, 2:1.9.4-1ubuntu0.1~esm1, 2:1.9.4-1ubuntu0.1~esm3, 2:1.9.4-2+deb9u1, 2:1.9.4-3ubuntu0.1, 2:1.9.4-3ubuntu0.1+esm2, 2.0-1
inetutils-ftp
2:1.9.2-1ubuntu0.1~esm2, 2:1.9.4-1ubuntu0.1~esm3, 2:1.9.4-3ubuntu0.1+esm2
inetutils-ftpd
2:1.9.2-1ubuntu0.1~esm2, 2:1.9.4-1ubuntu0.1~esm3, 2:1.9.4-3ubuntu0.1+esm2
inetutils-inetd
2:1.9.2-1ubuntu0.1~esm2, 2:1.9.4-1ubuntu0.1~esm3, 2:1.9.4-3ubuntu0.1+esm2
inetutils-ping
2:1.9.2-1ubuntu0.1~esm2, 2:1.9.4-1ubuntu0.1~esm3, 2:1.9.4-3ubuntu0.1+esm2
inetutils-syslogd
2:1.9.2-1ubuntu0.1~esm2, 2:1.9.4-1ubuntu0.1~esm3, 2:1.9.4-3ubuntu0.1+esm2
inetutils-talk
2:1.9.2-1ubuntu0.1~esm2, 2:1.9.4-1ubuntu0.1~esm3, 2:1.9.4-3ubuntu0.1+esm2
inetutils-talkd
2:1.9.2-1ubuntu0.1~esm2, 2:1.9.4-1ubuntu0.1~esm3, 2:1.9.4-3ubuntu0.1+esm2
inetutils-telnet
2:1.9.2-1ubuntu0.1~esm2, 2:1.9.4-1ubuntu0.1~esm3, 2:1.9.4-3ubuntu0.1+esm2
inetutils-telnetd
2:1.9.2-1ubuntu0.1~esm2, 2:1.9.4-1ubuntu0.1~esm3, 2:1.9.4-3ubuntu0.1+esm2
inetutils-tools
2:1.9.2-1ubuntu0.1~esm2, 2:1.9.4-1ubuntu0.1~esm3, 2:1.9.4-3ubuntu0.1+esm2
inetutils-traceroute
2:1.9.2-1ubuntu0.1~esm2, 2:1.9.4-1ubuntu0.1~esm3, 2:1.9.4-3ubuntu0.1+esm2
krb5-appl
0:1.0.1-10.el6_10, 1.0.3-3.3.1
krb5-appl-clients
1.0.1-10.el6_10, 1.0.3-3.3.1
krb5-appl-servers
1.0.1-10.el6_10, 1.0.3-3.3.1
Netkit Telnet
0.17, 0.17-18woody2, 0.17-5.ph4, 0.17-8.ph5
netkit-telnet-server
0.17-5.ph4, 0.17-8.ph5
netkit-telnet-ssl
0.17.17+0.1-2woody3
telnet
1:0.17-49.9.amzn1, 1:0.17-49.el6_10, 1:0.17-65.amzn2, 1:0.17-65.el7_6, 1:0.17-65.el7_8, 1:0.17-73.el8_0.1, 1:0.17-73.el8_1.1
telnet-server
1:0.17-49.9.amzn1, 1:0.17-49.el6_10, 1:0.17-65.amzn2, 1:0.17-65.el7_8, 1:0.17-73.el8_1.1
Timeline
Publicly disclosed
Jan 19, 2022
Last updated
Aug 5, 2026
Weakness Type
- CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer
- CWE-120 Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')
References
- advisoryhttp://access.redhat.com/errata/RHSA-2022:0007
- advisoryhttp://access.redhat.com/errata/RHSA-2022:0008
- advisoryhttp://access.redhat.com/errata/RHSA-2022:0158
- advisoryhttp://access.redhat.com/errata/RHSA-2022:0162
- advisoryRHSA-2020:1318
FAQ
Common Questions.
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: Netkit Telnet (Netkit Telnet Project); Communications Performance Intelligence Center (Oracle) versions 10.4.0.2; Eos (Arista) versions 4.24.0f, among others. The full list is in the CVE brief.
It is not listed in any known-exploited vulnerabilities catalog.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
No public exploit code is known.
Fixed versions are available, including Eos 4.20.15, inetutils 2:1.9.2-1ubuntu0.1~esm2, inetutils 2:1.9.2.39.3a460-3+deb8u1.
Brandefense priority: patch immediately, because it is very likely to be exploited soon.
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