CVE-2021-21371 | Execution of untrusted code through config file

Tenable for Jira Cloud is an open source project designed to pull Tenable.io vulnerability data, then generate Jira Tasks and sub-tasks based on the vulnerabilities' current state. It published in pypi as "tenable-jira-cloud". In tenable-jira-cloud before version 1.1.21, it is possible to run arbitrary commands through the yaml.load() method. This could allow an attacker with local access to the host to run arbitrary code by running the application with a specially crafted YAML configuration file. This is fixed in version 1.1.21 by using yaml.safe_load() instead of yaml.load().

Published: 2021-03-10 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2021-21371 is rated Low Risk (32.9/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.45%). Mandatory action: Monitor for updates and reassess as exploit intelligence or EPSS changes.

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-2021-21371

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 0.07% 0.45% +0.39%
2 2023-03-07 1.02% 0.07% -0.95%
3 2022-04-01 1.02%

Full EPSS history (6 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-21371

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.0 3.1 MEDIUM
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
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:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
1.8 2.7 [email protected]
8.6 3.1 HIGH
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H Click to expand
Attack vector (AV:L)
They already need access on the box, or another person has to do something wrong; it’s not a remote drive-by.
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:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
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: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.
1.8 6.0 [email protected]
4.6 2.0 MEDIUM
AV:L/AC:L/Au:N/C:P/I:P/A:P Click to expand
Access vector (AV:L)
Requires local access to the target system.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
3.9 6.4 [email protected]

Weakness enumeration for CVE-2021-21371

GitHub Security Advisory for CVE-2021-21371

GHSA-8278-88vv-x98r · Severity: medium · Ecosystem: pip — Execution of untrusted code through config file

Affected software / configurations for CVE-2021-21371

Vendor Product Version Raw CPE
tenable jira_cloud < 1.1.21 cpe:2.3:a:tenable:jira_cloud:*:*:*:*:*:*:*:*

References for CVE-2021-21371

cvelogic Threat Intelligence