CVE-2021-39132 [High] | Security Vulnerability in Rundeck

Rundeck is an open source automation service with a web console, command line tools and a WebAPI. Prior to version 3.3.14 and version 3.4.3, an authorized user can upload a zip-format plugin with a crafted plugin.yaml, or a crafted aclpolicy yaml file, or upload an untrusted project archive with a crafted aclpolicy yaml file, that can cause the server to run untrusted code on Rundeck Community or Enterprise Edition. An authenticated user can make a POST request, that can cause the server to run untrusted code on Rundeck Enterprise Edition. The zip-format plugin issues requires authentication and authorization to these access levels, and affects all Rundeck editions:`admin` level access to the `system` resource type. The ACL Policy yaml file upload issues requires authentication and authorization to these access levels, and affects all Rundeck editions: `create` `update` or `admin` level access to a `project_acl` resource, and/or`create` `update` or `admin` level access to the `system_acl` resource. The unauthorized POST request requires authentication, but no specific authorization, and affects Rundeck Enterprise only. Patches are available in versions 3.4.3, 3.3.14

#	Date	Old EPSS score	New EPSS score	Delta (New - Old)
1	2026-06-15	0.85%	1.38%	+0.53%
2	2026-02-11	0.65%	0.85%	+0.20%
3	2026-01-21	—	0.65%	—

Date

Old EPSS score

New EPSS score

Delta (New - Old)

2026-06-15

0.85%

1.38%

+0.53%

2026-02-11

0.65%

0.85%

+0.20%

2026-01-21

—

0.65%

—

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]
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]

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]

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]

Affected software / configurations for CVE-2021-39132

Vendor	Product	Version	Raw CPE
pagerduty	rundeck	< 3.3.14	cpe:2.3:a:pagerduty:rundeck:::::community:::*
pagerduty	rundeck	< 3.3.14	cpe:2.3:a:pagerduty:rundeck:::::enterprise:::*
pagerduty	rundeck	>= 3.4.0, < 3.4.3	cpe:2.3:a:pagerduty:rundeck:::::community:::*
pagerduty	rundeck	>= 3.4.0, < 3.4.3	cpe:2.3:a:pagerduty:rundeck:::::enterprise:::*

References for CVE-2021-39132

URL	Tags
https://github.com/rundeck/rundeck/commit/850d12e21d22833bc148b7f458d7cb5949f829b6	Patch Third Party Advisory
https://github.com/rundeck/rundeck/security/advisories/GHSA-q4rf-3fhx-88pf	Third Party Advisory

URL

CVE-2021-39132 | YAML deserialization can run untrusted code

Exploit prediction scoring system (EPSS) score for CVE-2021-39132

Common vulnerability scoring system (CVSS) metrics for CVE-2021-39132

Weakness enumeration for CVE-2021-39132

GitHub Security Advisory for CVE-2021-39132

Affected software / configurations for CVE-2021-39132

References for CVE-2021-39132