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CVE-2020-10188

INDEX BUILT · 2026-09-20

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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…

CVE-2020-101883 of 4 sources documented this
54

rank 54 = 19 + 25 + 0 + 10 + 0

rank@v1 · this cycle

Someone is already using it

CISA KEV catalog · public proof-of-concept · FIRST EPSS

EPSS 0.74339  ·  without this subject the record ranks 35

What it costs you if it fires

NVD CVSS base score, then the CNA's own

CVSS 9.8, from NVD  ·  without this subject the record ranks 29

It is getting worse, not staying still

FIRST EPSS series, rescorings and bad loads removed

no persisting rise in 365 days  ·  without this subject the record ranks 54

How much of the world it touches

NVD CPE configurations

20 products in the CPE ranges  ·  without this subject the record ranks 44

Someone else already set the date

CISA KEV remediation due date

no CISA due date  ·  without this subject the record ranks 54

Unaudited dollar value2 of 3 inputs carry a receipt
Exposure$3.71Mover the next 30 days, if this record is yours
Movement-$3.17Mon 2025-11-21, the last material move, 8 months before this reading
Basisassumeda published average, not your estate

$3.71M = $4.99M incident cost x 1 exposure x 0.74339 likelihood

udv@v1 · unaudited · wrong for you until you say what you run

$4.99M is the cost of a breach that happened, from IBM Cost of a Data Breach Report 2026, global average. It is not the value of any asset of yours. That average already covers breaches of every severity, so scaling it by exposure understates a partial-impact record. That is an assumption, not a measurement. Your own asset value goes in the decision record.

Hindsight · the state

0.74339EPSSNOT IN KEVas of 2026-09-20
Severity9.8 CRITICALreceipt
Harmtotal loss · unauthenticatedreceipt
Exploitationnone in held sources
Defenseno fix version held
Movementrisenreceipt
PLATEAU10Minimal movement since 2026-06-15, 43 days at 0.74, as of 2026-07-28. arc-rules@v1

Foresight · where to check next

SonicWall SonicOSCVE-2018-6789Zyxel ATP seriesCVE-2022-37055CVE-2020-1506910188

This record is one instance of CWE-120, buffer copy without checking size of input ('classic buffer overflow'). The index holds 4490 prior instances of this class, 24 KEV-listed. The nearest of its KEV-listed records are drawn beside this. taxonomy@v1

Full pattern panel

Prior records in this weakness class. Each is its own record, dated and receipted.
Color is a claim, not decoration:the hostile worldthe defenseno signalspoke length is how much of the record matches, not how bad it is

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Harm, if it fires from the vector and the weakness

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Reachnetwork-reachable · no privileges required · no user interaction · low attack complexityreceipt
ImpactComplete confidentiality, integrity and availability lossreceipt
Scored fromCVSS v3.1 · NVD's vectorreceipt
Weakness classCWE-120 Buffer Copy without Checking Size of Input ('Classic Buffer Overflow')receipt
Published consequencesCWE-120: Integrity, Confidentiality, Availability: Modify Memory, Execute Unauthorized Code or Commands; Availability: Modify Memory, DoS: Crash, Exit, or Restart, DoS: Resource Consumption (CPU)[email protected]

CISA KEV & Federal Remediation Deadline from the record and CISA

The fix, and how long it's been waiting.

Fixed inNo fix version in held sources, as the index stood on 28 Jul 2026.
Patch available sinceNo dated patch-availability record in held sources. The index holds reference URLs without dates and only the current revision of the CVE record, so the day a fix first existed cannot be derived. Only the versions it landed in.

Exploit Status & Known PoCs a ladder, not a score

Current rung: Nothing observed in held sources.

  • RUNG 1Nothing observed in held sources
  • RUNG 2Proof-of-concept published
  • RUNG 3Exploited in the wild · CISA KEV listed
  • RUNG 4Ransomware campaign use known

Authority who says so

CVSS, NVD9.8 CRITICALreceipt
Exploit probability0.74339 · top 0.53% of all CVEsreceipt
Blast breadth6 products across 6 vendorsderived
Assigned bymitrereceipt
Recorded changes42 · last 18 Sep 2026derived

Affected & Fixed Versions as published

Named in the CPE rangesNetkit telnet project netkit telnet; Juniper junos; Arista eos; and 3 morereceipt
Published rangesnetkit telnet project netkit telnet <= 0.17; fedoraproject fedora 30; fedoraproject fedora 31; fedoraproject fedora 32receipt
Show all 20 published ranges
netkit telnet project netkit telnet <= 0.17
fedoraproject fedora 30
fedoraproject fedora 31
fedoraproject fedora 32
debian linux 8.0
debian linux 9.0
arista eos <= 4.20.15
arista eos >= 4.21.0 <= 4.21.10m
arista eos >= 4.22 <= 4.22.4m
arista eos >= 4.23 <= 4.23.3m
arista eos 4.24.0f
oracle communications performance intelligence center 10.4.0.2
juniper junos 12.3
juniper junos 12.3r12
juniper junos 12.3x48
juniper junos 12.3x50
juniper junos 15.1
juniper junos 15.1x49
juniper junos 15.1x49-d30
juniper junos 15.1x49-d60

A rung lights from a row in the index, never from an assessment. "Held sources" is the true scope of the claim: this index reads the CVE record, NVD, CISA KEV, FIRST's EPSS and public proof-of-concept repositories, and it does not observe attacks.

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What it is stated by the CNA

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. receipt

NVD's analysis a second authority

severity
9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
weakness
CWE-120
affected versions
netkit telnet project netkit telnet <= 0.17; fedoraproject fedora 30; fedoraproject fedora 31; and 17 more, listed in full below

check it yourself lists.fedoraproject.org lists.fedoraproject.org lists.fedoraproject.org lists.debian.org tools.cisco.com lists.debian.org +4 morereceipt

Dated events

2022-01-06EPSS moved 0.05 to 0.192023-03-07EPSS moved 0.10 to 0.942026-06-15EPSS moved 0.08 to 0.75

Movement the material steps

14 Apr 20210.04044
6 Jan 20220.18794 · crossed 0.10
4 Feb 20220.67992 · crossed 0.50
1 Apr 20220.09801 · crossed 0.10 and 0.50
7 Mar 20230.93808 · crossed 0.10 and 0.50 and 0.90 · scoring model v2023.03.01
8 Nov 20230.85227 · crossed 0.90
17 Dec 20240.64554
17 Mar 20250.1193 · crossed 0.50 · scoring model v2025.03.14
29 Mar 20250.23878
30 Mar 20250.11653
15 Apr 20250.09149 · crossed 0.10
23 Apr 20250.11448 · crossed 0.10
30 Aug 20250.08929 · crossed 0.10
18 Nov 20250.72355 · crossed 0.10 and 0.50
21 Nov 20250.08766 · crossed 0.10 and 0.50
15 Jun 20260.74513 · crossed 0.10 and 0.50 · scoring model v2026.06.15
28 Jul 20260.74339
Show all 42 observations
14 Apr 20210.04044
15 Jun 20210.04476
9 Nov 20210.04905
6 Jan 20220.18794
4 Feb 20220.67992
1 Apr 20220.09801
7 Mar 20230.93808
24 Mar 20230.92813
8 May 20230.93609
8 Jul 20230.92813
8 Nov 20230.85227
9 Jan 20240.81898
11 Feb 20240.83252
17 Dec 20240.64554
28 Feb 20250.70048
17 Mar 20250.1193
20 Mar 20250.11653
29 Mar 20250.23878
30 Mar 20250.11653
15 Apr 20250.09149
23 Apr 20250.11448
24 Apr 20250.11181
30 Aug 20250.08929
16 Sep 20250.06951
19 Sep 20250.06779
30 Sep 20250.08699
2 Oct 20250.06434
7 Oct 20250.06951
22 Oct 20250.06779
23 Oct 20250.08553
18 Nov 20250.72355
21 Nov 20250.08766
4 Dec 20250.08553
21 Jan 20260.08404
21 Mar 20260.08614
23 Mar 20260.08404
5 Apr 20260.09578
7 Apr 20260.08404
11 Apr 20260.09578
10 May 20260.08404
15 Jun 20260.74513
28 Jul 20260.74339

42 observations held. A highlighted step crossed a promotion threshold. A step marked with a scoring model moved because the instrument was replaced, not because the vulnerability changed. receipt

The full biography

EPSS 0.74339Published2020-03-06Index as of2026-07-28

The record had been public for 6 years, 4 months when this index was last written.

Published 2020-03-06 receipt · Index as of 2026-07-28 derived

The pattern, elsewhere

This record is one instance of CWE-120, buffer copy without checking size of input ('classic buffer overflow'). The index holds 4490 prior instances of this class, 24 KEV-listed. The nearest of its KEV-listed records are drawn beside this. [email protected]

CVE-2020-5135 · SonicWall SonicOSmatches 8 of 8KEV listed · 2020receipt
CVE-2018-6789matches 8 of 8KEV listed · 2018receipt
CVE-2023-33009 · Zyxel ATP series firmwarematches 8 of 8KEV listed · 2023receipt
CVE-2023-33010 · Zyxel ATP series firmwarematches 8 of 8KEV listed · 2023receipt
CVE-2022-37055matches 8 of 8KEV listed · 2022receipt
CVE-2020-15069matches 8 of 8KEV listed · 2020receipt

"Matches n of m" counts the attributes the two records can both be compared on: the CVSS metrics they share a version of, any weakness class beyond this one, and the vendor. fit-rules@v1

4490 records in this class held. The six above are drawn from the ones CISA has listed as exploited, ranked by how much of the record matches this one. That is why every one of them is KEV-listed: the pool is, so the colour on those spokes says nothing the pool has not already said.

No curated product neighbourhood is held for this product, so the records above are the nearest this index can name. The neighbourhood table covers a small set of products and is extended by hand.

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