CVE-2021-36121

An issue was discovered in Echo ShareCare 8.15.5. The file-upload feature in Access/DownloadFeed_Mnt/FileUpload_Upd.cfm is susceptible to an unrestricted upload vulnerability via the name1 parameter, when processing remote input from an authenticated user, leading to the ability for arbitrary files to be written to arbitrary filesystem locations via ../ Directory Traversal on the Z: drive (a hard-coded drive letter where ShareCare application files reside) and remote code execution as the ShareCare service user (NT AUTHORITY\SYSTEM).

Published: 2021-07-13 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-36121 is rated Moderate Risk (63.2/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.67%). 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-2021-36121

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 2025-11-21 2.25% 1.67% -0.58%
2 2025-11-18 1.67% 2.25% +0.58%
3 2025-03-30 — 1.67% —

Full EPSS history (12 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-36121

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.8 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/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:L)
A normal user session is enough; they don’t have to be admin.
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:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.8 5.9 [email protected]
6.5 2.0 MEDIUM
AV:N/AC:L/Au:S/C:P/I:P/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:S)
A single authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 8.0 6.4 [email protected]

Weakness enumeration for CVE-2021-36121

Affected software / configurations for CVE-2021-36121

Vendor Product Version Raw CPE
echobh sharecare 8.15.5 cpe:2.3:a:echobh:sharecare:8.15.5:*:*:*:*:*:*:*

References for CVE-2021-36121

cvelogic Threat Intelligence