CVE-2021-36770

Gentoo Linux Security Advisory 202411-09

Severity Score

7.8

*CVSS v3.1

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

*Multiple Sources

Exploited in Wild

*KEV

Decision

*SSVC

Descriptions

Encode.pm, as distributed in Perl through 5.34.0, allows local users to gain privileges via a Trojan horse Encode::ConfigLocal library (in the current working directory) that preempts dynamic module loading. Exploitation requires an unusual configuration, and certain 2021 versions of Encode.pm (3.05 through 3.11). This issue occurs because the || operator evaluates @INC in a scalar context, and thus @INC has only an integer value.

Encode.pm, distribuido en Perl versiones hasta 5.34.0, permite a usuarios locales alcanzar privilegios por medio de una biblioteca Encode::ConfigLocal (en el directorio de trabajo actual) que se adelanta a una carga dinámica de módulos. Una explotación requiere una configuración inusual, y determinadas versiones 2021 de Encode.pm (3.05 hasta 3.11). Este problema ocurre porque el operador || evalúa @INC en un contexto escalar, y por lo tanto @INC sólo tiene un valor entero

It was discovered that the Perl Encode library incorrectly handled paths. A local attacker could possibly use this issue to trick the library into executing arbitrary code from the current working directory.

*Credits: N/A

Attack Vector

Local

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Attack Vector

Network

Attack Complexity

Medium

Authentication

None

Confidentiality

Partial

Integrity

Partial

Availability

Partial

* Common Vulnerability Scoring System

SSVC

Decision:-

Exploitation

Automatable

Tech. Impact

* Organization's Worst-case Scenario

Timeline

2021-07-17 CVE Reserved
2021-08-10 CVE Published
2024-08-04 CVE Updated
2025-03-30 EPSS Updated
---------- Exploited in Wild
---------- KEV Due Date
---------- First Exploit

CWE

CWE-427: Uncontrolled Search Path Element

CAPEC

References (8)

URL	Tag	Source
https://metacpan.org/dist/Encode/changes	Third Party Advisory
https://news.cpanel.com/unscheduled-tsr-10-august-2021	Third Party Advisory
https://security-tracker.debian.org/tracker/CVE-2021-36770	Third Party Advisory
https://security.netapp.com/advisory/ntap-20210909-0003	Third Party Advisory

URL	Date	SRC

URL	Date	SRC
https://github.com/Perl/perl5/commit/c1a937fef07c061600a0078f4cb53fe9c2136bb9	2023-11-07
https://github.com/dankogai/p5-encode/commit/527e482dc70b035d0df4f8c77a00d81f8d775c74	2023-11-07

URL	Date	SRC
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/5NDGQSGMEZ75FJGBKNYC75OTO7TF7XHB	2023-11-07
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/6KOZYD7BH2DNIAEZ2ZL4PJ4QUVQI6Y33	2023-11-07

Affected Vendors, Products, and Versions

Vendor		Product				Version		Other		Status
Vendor	Product	Version	Other	Status	<-- -->	Vendor	Product	Version	Other	Status
P5-encode Project Search vendor "P5-encode Project"	P5-encode Search vendor "P5-encode Project" for product "P5-encode"	>= 3.05 < 3.12 Search vendor "P5-encode Project" for product "P5-encode" and version " >= 3.05 < 3.12"	-	Affected	in	Perl Search vendor "Perl"	Perl Search vendor "Perl" for product "Perl"	<= 5.34.0 Search vendor "Perl" for product "Perl" and version " <= 5.34.0"	-	Safe
Fedoraproject Search vendor "Fedoraproject"		Fedora Search vendor "Fedoraproject" for product "Fedora"				34 Search vendor "Fedoraproject" for product "Fedora" and version "34"		-		Affected
Fedoraproject Search vendor "Fedoraproject"		Fedora Search vendor "Fedoraproject" for product "Fedora"				33 Search vendor "Fedoraproject" for product "Fedora" and version "33"		-		Affected