CVE-2020-11637 | Automation Runtime TFTP Service DoS Vulnerability

A memory leak in the TFTP service in B&R Automation Runtime versions <N4.26, <N4.34, <F4.45, <E4.53, <D4.63, <A4.73 and prior could allow an unauthenticated attacker with network access to cause a denial of service (DoS) condition.

Published: 2020-10-15 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2020-11637 is rated Moderate Risk (45.2/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 1.08%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2020-11637

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.25% 1.08% +0.82%
2 2025-03-17 0.10% 0.25% +0.16%
3 2023-03-07 — 0.10% —

Full EPSS history (7 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2020-11637

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.8 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
 3.9 1.4 [email protected]
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:N/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 2.9 [email protected]

Weakness enumeration for CVE-2020-11637

Affected software / configurations for CVE-2020-11637

Vendor Product Version Raw CPE
br-automation automation_runtime <= 4.10 cpe:2.3:a:br-automation:automation_runtime:*:*:*:*:*:*:*:*
br-automation automation_runtime >= 4.20, < n4.26 cpe:2.3:a:br-automation:automation_runtime:*:*:*:*:*:*:*:*
br-automation automation_runtime >= 4.40, < f4.45 cpe:2.3:a:br-automation:automation_runtime:*:*:*:*:*:*:*:*
br-automation automation_runtime >= 4.50, < e4.53 cpe:2.3:a:br-automation:automation_runtime:*:*:*:*:*:*:*:*
br-automation automation_runtime >= 4.60, < d4.63 cpe:2.3:a:br-automation:automation_runtime:*:*:*:*:*:*:*:*
br-automation automation_runtime >= 4.70, < a4.73 cpe:2.3:a:br-automation:automation_runtime:*:*:*:*:*:*:*:*
br-automation automation_runtime >= 4.30, < n4.34 cpe:2.3:a:br-automation:automation_runtime:*:*:*:*:*:*:*:*

References for CVE-2020-11637

cvelogic Threat Intelligence