Cyber Resilience

CVE-2020-10188

Memory Safety in Juniper Junos 12.3 … 20.1

High EPSSMemory Safety
Published
06 March 2020
Modified
21 January 2026
Patch / advisory
CVSS Score v3.1 9.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.74 99.4th percentile
Risk Priority 97 floored blend · peak EPSS

Summary

CVE-2020-10188 is a critical-severity Classic Buffer Overflow (CWE-120) vulnerability in Juniper Junos. Its CVSS base score is 9.8 (Critical).

Operationally, ranked in the top 0.6% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

EU & UK References

Vulnerability Data

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.

CWE(s)

Related Threats

Likely ATT&CK TechniquesAI

Techniques this vulnerability likely enables, inferred from its description, weakness type, and attributed-actor tradecraft. Confidence is per-technique.

T1190 Exploit Public-Facing Application Initial Accessconfidence: HIGH
The telnetd daemon is a publicly reachable network service and the buffer overflow in netclear/nextitem directly enables remote code execution against it.
T1059 Command and Scripting Interpreter Executionconfidence: MEDIUM
Successful exploitation yields arbitrary command execution on the target host.
inferred from description + CWE · MITRE ATT&CK Enterprise v19.0

CVEs Like This One

CVE-2023-40589Same product: Debian Debian Linux
CVE-2020-11984Same product: Debian Debian Linux
CVE-2020-8625Same product: Debian Debian Linux
CVE-2023-22399Same product: Juniper Junos
CVE-2024-39543Same product: Juniper Junos
CVE-2023-51798Same product: Fedoraproject Fedora
CVE-2025-25472Same product: Debian Debian Linux
CVE-2023-4055Same product: Debian Debian Linux
CVE-2024-24479Same product: Fedoraproject Fedora
CVE-2024-35823Same product: Debian Debian Linux

Affected Assets

netkit telnet project
netkit telnet
≤ 0.17
fedoraproject
fedora
30, 31, 32
debian
debian linux
8.0, 9.0
arista
eos
4.24.0f · ≤ 4.20.15 · 4.21.0 — 4.21.10m · 4.22 — 4.22.4m
oracle
communications performance intelligence center
10.4.0.2
juniper
junos
12.3, 12.3r12, 12.3x48, 12.3x50, 15.1

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)

Validate
Prove the fix (OWASP ASVS)
  • V5.2.1

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-120

Platform-independent managed code eliminates the need for unchecked native buffer copies that are the root cause of classic buffer overflows.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.PS-06 mostly match
prevents

Secure development practices directly enforce bounds checking and input validation that prevent classic buffer overflows.

ID.RA-01 partial match
prevents

Vulnerability identification processes such as code review or scanning detect classic buffer overflows before exploitation.

PR.PS-02 partial match
prevents

Routine patching replaces vulnerable code containing unchecked buffer copies with corrected versions.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

prevents

Secure coding directly requires bounds-checked memory operations, addressing the root cause of CWE-120.

detects

Security testing in development and acceptance can detect buffer overflows through fuzzing and static analysis, though it does not prevent them at the source.

prevents

Secure development life cycle mandates processes that can include input validation and bounds checking to prevent buffer overflows.

prevents

Application security requirements can specify input-size validation and safe buffer handling to mitigate classic buffer overflows.

prevents

Secure system architecture and engineering principles promote defensive coding patterns that reduce the likelihood of unchecked buffer copies.

References