Cyber Resilience

CVE-2021-3560

Access Control in Polkit Project Polkit ≤ 0.119

CISA KEVActive ExploitationEUVD ExploitedPublic PoCAccess Control
Published
16 February 2022
Modified
06 November 2025
KEV Added
12 May 2023
Patch / advisory
CVSS Score v3.1 7.8
Click a component to see what it means
Raw vectorCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS Score 0.22 97th percentile
Risk Priority 83 floored blend · peak EPSS

Summary

CVE-2021-3560 is a high-severity Incorrect Authorization (CWE-863) vulnerability in Redhat Enterprise Linux. Its CVSS base score is 7.8 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked in the top 3% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog; a public proof-of-concept is referenced.

Deeper analysis AI-assisted summary

Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.

CVE-2021-3560 is a privilege escalation flaw in polkit that allows the component to be tricked into bypassing credential checks for D-Bus requests. Successful exploitation elevates the privileges of the requestor to the root user. The vulnerability is tracked under CWE-863 and CWE-754 and carries a CVSS 3.1 base score of 7.8.

An unprivileged local attacker can exploit the issue to perform actions such as creating a new local administrator account. The attack requires local access, low attack complexity, and no user interaction, resulting in high impact to confidentiality, integrity, and availability.

Public references, including a Red Hat Bugzilla entry and a detailed analysis on the GitHub Security Lab blog, discuss the flaw and link to related proof-of-concept material on Packet Storm.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

It was found that polkit could be tricked into bypassing the credential checks for D-Bus requests, elevating the privileges of the requestor to the root user. This flaw could be used by an unprivileged local attacker to, for example, create…

more

a new local administrator. The highest threat from this vulnerability is to data confidentiality and integrity as well as system availability.

CWE(s)
KEV Date Added
12 May 2023

Related Threats

MITRE ATT&CK Enterprise Techniques

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
T1489 Service Stop Impact
Adversaries may stop or disable services on a system to render those services unavailable to legitimate users.
T1499 Endpoint Denial of Service Impact
Adversaries may perform Endpoint Denial of Service (DoS) attacks to degrade or block the availability of services to users.
T1499.004 Application or System Exploitation Impact
Adversaries may exploit software vulnerabilities that can cause an application or system to crash and deny availability to users.
T1548 Abuse Elevation Control Mechanism Privilege Escalation
Adversaries may circumvent mechanisms designed to control privilege elevation to gain higher-level permissions.
T1548.002 Bypass User Account Control Privilege Escalation
Adversaries may bypass UAC mechanisms to elevate process privileges on system.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2021-3493Same product: Canonical Ubuntu Linuxboth on KEV
CVE-2022-0543Same product: Canonical Ubuntu Linuxboth on KEV
CVE-2018-6789Same product: Canonical Ubuntu Linuxboth on KEV
CVE-2023-21715Shared CWE-863both on KEV
CVE-2025-55177Shared CWE-863both on KEV
CVE-2023-38035Shared CWE-863both on KEV
CVE-2021-30533Shared CWE-863both on KEV
CVE-2021-40655Shared CWE-863both on KEV
CVE-2019-7192Shared CWE-863both on KEV
CVE-2025-21479Shared CWE-863both on KEV

Affected Assets

polkit project
polkit
≤ 0.119
debian
debian linux
11.0
canonical
ubuntu linux
20.04
redhat
virtualization
4.0
redhat
virtualization host
4.0
redhat
openshift container platform
4.7

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

Detect
Catch it (NIST detect / respond)

Harden
Shrink the surface (DISA STIG)
  • 12 hardening rules · 4 OS baselines
Validate
Prove the fix (OWASP ASVS)

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

addresses: CWE-863

Periodic review and update of procedures reduces incorrect authorization implementations over time.

addresses: CWE-863

Supervision identifies cases where authorization logic incorrectly permits unauthorized actions.

addresses: CWE-863

Defining permitted attribute values and auditing modifications reduces the chance of incorrect authorization outcomes due to tampered or missing labels.

addresses: CWE-863

The authorization process and usage restrictions help prevent incorrect authorization for remote access types.

addresses: CWE-863

Establishing configuration and connection requirements helps ensure correct rather than incorrect authorization for wireless access.

addresses: CWE-863

Establishing connection authorization processes for mobile devices helps ensure authorization decisions are correctly implemented rather than incorrect.

addresses: CWE-863

Monitoring account use, notifying on changes, and reviewing accounts for compliance corrects incorrect authorization assignments.

addresses: CWE-863

Ensures authorization decisions for external system use are correctly implemented and enforced.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.AA-05 mostly match
prevents

Defining, enforcing, and reviewing access authorizations and least privilege directly prevents incorrect authorization checks.

PR.PS-06 mostly match
prevents

Secure development practices directly require proper checks and handling for exceptional conditions throughout the SDLC.

DE.CM-09 partial match
prevents

Runtime monitoring of software and environments can detect adverse events triggered by unhandled exceptional conditions.

PR.PS-04 partial match
prevents

Generating logs of exceptions and errors enables detection of improper handling of unusual conditions.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

finds

Security testing in development and acceptance verifies handling of error and exceptional conditions.

prevents

Requiring consistency between access rights and classification plus formal approval steps ensures that the authorization logic correctly distinguishes between entities that should and should not be granted access.

prevents

Enforcing policy-driven approval and role-change reviews stops incorrect or stale authorization decisions from remaining in effect after job changes or terminations.

A.8.15 Logging partial match
finds

Logging can record unhandled exceptions but does not prevent the weakness itself.

finds

Monitoring may detect symptoms of unhandled conditions but does not eliminate the root weakness.

prevents

Secure development life cycle mandates exception handling and input validation that directly prevent missing checks for unusual conditions.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

Oracle Linux 8 (4 rules)
  • V-248574 YUM must be configured to prevent the installation of patches, service packs, device drivers, or OL 8 system components that have not been digitally signed using a certificate that is recognized and approved by the organization. prevents CWE-754
  • V-248581 OL 8 must require users to provide a password for privilege escalation. prevents CWE-863
  • V-248575 OL 8 must prevent the installation of software, patches, service packs, device drivers, or operating system components of local packages without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-754
Oracle Linux 9 (1 rule)
  • V-271452 OL 9 must use a Linux Security Module configured to enforce limits on system services. prevents CWE-754
RHEL 7 (1 rule)
  • V-204430 The Red Hat Enterprise Linux operating system must be configured so that users must re-authenticate for privilege escalation. prevents CWE-863
RHEL 8 (1 rule)
  • V-251712 The RHEL 8 operating system must not be configured to bypass password requirements for privilege escalation. prevents CWE-863

References