CVE-2021-20876

Path traversal vulnerability in GroupSession Free edition ver5.1.1 and earlier, GroupSession byCloud ver5.1.1 and earlier, and GroupSession ZION ver5.1.1 and earlier allows an attacker with an administrative privilege to obtain sensitive information stored in the hierarchy above the directory on the published site's server via unspecified vectors.

Published: 2021-12-24 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-20876 is rated Moderate Risk (42.2/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.23%). 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-2021-20876

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 2025-03-30 0.46% 0.23% -0.22%
2 2025-03-29 0.23% 0.46% +0.22%
3 2025-03-17 — 0.23% —

Full EPSS history (8 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-20876

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.8 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:N/A:N 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:H)
They need powerful rights—admin, root, or similar—before this pays off.
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:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 2.3 4.0 [email protected]
4.0 2.0 MEDIUM
AV:N/AC:L/Au:S/C:P/I:N/A:N 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:N)
No integrity impact.
Availability impact (A:N)
No availability impact.
 8.0 2.9 [email protected]

Weakness enumeration for CVE-2021-20876

Affected software / configurations for CVE-2021-20876

Vendor Product Version Raw CPE
groupsession groupsession <= 5.1.1 cpe:2.3:a:groupsession:groupsession:*:*:*:*:cloud:*:*:*
groupsession groupsession <= 5.1.1 cpe:2.3:a:groupsession:groupsession:*:*:*:*:free:*:*:*
groupsession groupsession <= 5.1.1 cpe:2.3:a:groupsession:groupsession:*:*:*:*:zion:*:*:*

References for CVE-2021-20876

cvelogic Threat Intelligence