CVE-2020-10188

CRITICALNVD 9.89.8—
EchelonGraph scoreMEDIUM confidence

Score 9.8 from GitHub Security Advisory (severity: HIGH) published 2022-05-24. NVD baseline CVSS 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
Trending — 3 sources updated this weekElevated
9.8
EchelonGraph verdictPatch this weekExploitation is likely or a public exploit exists.
  • High exploitation likelihood — EPSS 75%
CISA-KEV: Not listedEPSS: 75%CVSS: 9.8Exploit: NoneExposed: 0

A fix is available — apply it.

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.

CVSS v3
9.8
EG Score
9.8(medium)
EG Risk
78(Track*)
EG Risk 78/100SSVC: Track*

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity98% × 45%
Exploitation75% × 40%
Automatability30% × 15%
Action: Watch closely — could escalate to Attend.
EPSS
99.4%
KEV
Not listed

Published

March 6, 2020

Last Modified

January 21, 2026

Advisory Details (9)

Auto-updated Jul 8, 2026
🔬 Proof of concept available. Patch available.
generic

Security Advisory 0048 - Arista

https://www.arista.com/en/support/advisories-notices/security-advisories/10702-security-advisory-48
generic🟡 PoC Available

Telnet Vulnerability Affecting Cisco Products: June 2020

https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-telnetd-EFJrEzPx
generic

[SECURITY] Fedora 30 Update: telnet-0.17-77.fc30 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/K3VJ6V2Z3JRNJOBVHSOPMAC76PSSKG6A/
generic

[SECURITY] Fedora 32 Update: telnet-0.17-79.fc32 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/HLU6FL24BSQQEB2SJC26NLJ2MANQDA7M/
generic

[SECURITY] Fedora 31 Update: telnet-0.17-78.fc31 - package-announce - Fedora mailing-lists

https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/7FMTRRQTYKWZD2GMXX3GLZV46OLPCLVK/
generic Patch Available

[SECURITY] [DLA 2341-1] inetutils security update

https://lists.debian.org/debian-lts-announce/2020/08/msg00038.html
generic Patch Available

[SECURITY] [DLA 2176-1] inetutils security update

https://lists.debian.org/debian-lts-announce/2020/05/msg00012.html
generic

krb5-appl/telnet/telnetd/utility.c at d00cd671dfe945791b33d4f1f6a5c57ae1667ef8 · krb5/krb5-appl · GitHub

https://github.com/krb5/krb5-appl/blob/d00cd671dfe945791b33d4f1f6a5c57ae1667ef8/telnet/telnetd/utility.c#L205-L216
generic🟡 PoC Available

APPGate Research Blog: BraveStarr – A Fedora 31 netkit telnetd remote exploit

https://appgateresearch.blogspot.com/2020/02/bravestarr-fedora-31-netkit-telnetd_28.html

Patch Availability(10)

Vendor / EcosystemFixed in / PatchReleasedSource
ubuntuinetutils-telnet (2:1.9.4-11ubuntu0.1) @ focal2026-05-27ubuntu
ubuntuinetutils-telnet (2:1.9.4-1ubuntu0.1~esm1) @ xenial2026-05-27ubuntu
ubuntuinetutils-traceroute (2:1.9.4-1ubuntu0.1~esm3) @ xenial2026-05-27ubuntu
redhattelnet-1:0.17-65.el7_72022-01-18redhat
redhattelnet-1:0.17-65.el7_62022-01-04redhat
redhatkrb5-appl-0:1.0.1-10.el6_102020-04-07redhat
redhattelnet-1:0.17-73.el8_0.12020-04-07redhat
redhattelnet-1:0.17-65.el7_82020-04-06redhat
redhattelnet-1:0.17-73.el8_1.12020-04-06redhat
redhattelnet-1:0.17-49.el6_102020-04-06redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

All Vendor Advisories

(10)

Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.

Data Freshness Timeline

(refreshed 7× in last 7d / 26× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-23 01:48 UTCEG score recompute
  2. 2026-07-22 22:32 UTCEG score recompute
  3. 2026-07-22 14:05 UTCEPSS rescore
  4. 2026-07-20 17:04 UTCEPSS rescore
  5. 2026-07-19 18:18 UTCOSV refresh
  6. 2026-07-19 02:26 UTCEPSS rescore
  7. 2026-07-19 02:26 UTCEPSS rescore
  8. 2026-07-15 16:55 UTCEPSS rescore
  9. 2026-07-13 06:10 UTCEPSS rescore
  10. 2026-07-13 06:10 UTCEPSS rescore
  11. 2026-07-11 08:24 UTCEPSS rescore
  12. 2026-07-08 15:11 UTCEPSS rescore
  13. 2026-07-05 02:27 UTCEPSS rescore
  14. 2026-07-02 07:17 UTCOSV refresh
  15. 2026-07-01 15:03 UTCEPSS rescore
  16. 2026-07-01 15:03 UTCEPSS rescore
  17. 2026-06-30 23:20 UTCEPSS rescore
  18. 2026-06-30 23:20 UTCEPSS rescore
  19. 2026-06-29 14:04 UTCEPSS rescore
  20. 2026-06-29 14:04 UTCEPSS rescore
  21. 2026-06-28 14:05 UTCEPSS rescore
  22. 2026-06-27 03:06 UTCEPSS rescore
  23. 2026-06-25 13:47 UTCEPSS rescore
  24. 2026-06-25 13:47 UTCEPSS rescore
  25. 2026-06-24 14:03 UTCEPSS rescore
Show 45 more
  1. 2026-06-24 14:03 UTCEPSS rescore
  2. 2026-06-23 21:31 UTCEPSS rescore
  3. 2026-06-23 21:31 UTCEPSS rescore
  4. 2026-06-17 17:50 UTCEPSS rescore
  5. 2026-06-17 17:50 UTCEPSS rescore
  6. 2026-06-15 17:46 UTCEPSS rescore
  7. 2026-06-14 23:15 UTCEPSS rescore
  8. 2026-06-14 23:15 UTCEPSS rescore
  9. 2026-06-14 07:43 UTCOSV refresh
  10. 2026-06-13 22:58 UTCEPSS rescore
  11. 2026-06-13 22:58 UTCEPSS rescore
  12. 2026-06-12 23:09 UTCEPSS rescore
  13. 2026-06-11 13:58 UTCEPSS rescore
  14. 2026-06-10 22:16 UTCEPSS rescore
  15. 2026-06-10 22:16 UTCEPSS rescore
  16. 2026-06-10 13:20 UTCEPSS rescore
  17. 2026-06-08 14:15 UTCEPSS rescore
  18. 2026-06-08 14:15 UTCEPSS rescore
  19. 2026-06-07 15:23 UTCEPSS rescore
  20. 2026-06-07 15:23 UTCEPSS rescore
  21. 2026-06-06 13:45 UTCEPSS rescore
  22. 2026-06-06 13:45 UTCEPSS rescore
  23. 2026-06-06 13:45 UTCEPSS rescore
  24. 2026-06-05 22:45 UTCEPSS rescore
  25. 2026-06-05 22:45 UTCEPSS rescore
  26. 2026-06-05 06:08 UTCEPSS rescore
  27. 2026-06-04 13:10 UTCEPSS rescore
  28. 2026-06-04 13:10 UTCEPSS rescore
  29. 2026-06-02 20:11 UTCEPSS rescore
  30. 2026-06-02 20:11 UTCEPSS rescore
  31. 2026-06-01 13:50 UTCEPSS rescore
  32. 2026-05-31 22:29 UTCEPSS rescore
  33. 2026-05-31 22:29 UTCEPSS rescore
  34. 2026-05-31 00:15 UTCEPSS rescore
  35. 2026-05-31 00:14 UTCEPSS rescore
  36. 2026-05-29 13:42 UTCEPSS rescore
  37. 2026-05-29 13:42 UTCEPSS rescore
  38. 2026-05-28 13:43 UTCEPSS rescore
  39. 2026-05-28 13:43 UTCEPSS rescore
  40. 2026-05-27 13:39 UTCEPSS rescore
  41. 2026-05-27 06:59 UTCEG score recompute
  42. 2026-05-27 06:59 UTCVendor advisory
  43. 2026-05-27 06:59 UTCGHSA enrichment
  44. 2026-05-26 13:42 UTCEPSS rescore
  45. 2026-05-26 13:42 UTCEPSS rescore

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Frequently asked(5)

What is CVE-2020-10188?
CVE-2020-10188 is a critical vulnerability published on March 6, 2020. 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.
When was CVE-2020-10188 disclosed?
CVE-2020-10188 was first published in the National Vulnerability Database on March 6, 2020, with the most recent update on January 21, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2020-10188 actively exploited?
CVE-2020-10188 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 99.4% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2020-10188?
CVE-2020-10188 has a CVSS v3 base score of 9.8 (NVD).
How do I remediate CVE-2020-10188?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2020-10188, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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