Security Resilience

CVE-2023-43582

Auth Bypass in Zoom Meetings ≤ 5.16.0

Published
15 November 2023
Modified
21 November 2024
Patch / advisory
CVSS Score v3.1 5.5
Click a component to see what it means
Raw vectorCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:L/I:L/A:L
EPSS Score 0.0066 50th percentile
Risk Priority 44 floored blend · peak EPSS

CVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.

Summary

CVE-2023-43582 is a medium-severity Improper Authorization in Handler for Custom URL Scheme (CWE-939) vulnerability in Zoom Meetings. Its CVSS base score is 5.5 (Medium).

Operationally, exploitation aligns with the MITRE ATT&CK technique Security Account Manager (T1003.002); ranked in the top 50% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.

OWASP Top 10 for Web (2025)

EU & UK References

Vulnerability Data

Improper authorization in some Zoom clients may allow an authorized user to conduct an escalation of privilege via network access.

CWE(s)

Related Threats

MITRE ATT&CK Enterprise Techniques

T1003.002 Security Account Manager Credential Access
Adversaries may attempt to extract credential material from the Security Account Manager (SAM) database either through in-memory techniques or through the Windows Registry where the SAM database is stored.
T1003.004 LSA Secrets Credential Access
Adversaries with SYSTEM access to a host may attempt to access Local Security Authority (LSA) secrets, which can contain a variety of different credential materials, such as credentials for service accounts.
T1007 System Service Discovery Discovery
Adversaries may try to gather information about registered local system services.
T1016 System Network Configuration Discovery Discovery
Adversaries may look for details about the network configuration and settings, such as IP and/or MAC addresses, of systems they access or through information discovery of remote systems.
T1016.001 Internet Connection Discovery Discovery
Adversaries may check for Internet connectivity on compromised systems.
T1016.002 Wi-Fi Discovery Discovery
Adversaries may search for information about Wi-Fi networks, such as network names and passwords, on compromised systems.
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-39199Same product: Zoom Meetings
CVE-2023-39204Same product: Zoom Meetings
CVE-2023-39206Same product: Zoom Meetings
CVE-2023-36532Same product: Zoom Rooms
CVE-2023-43588Same product: Zoom Meetings
CVE-2023-36535Same product: Zoom Rooms
CVE-2023-22880Same product: Zoom Rooms
CVE-2026-53407Same vendor: Zoom
CVE-2026-53408Same vendor: Zoom
CVE-2023-39218Same product: Zoom Rooms

Affected Assets

zoom
meetings
≤ 5.16.0 · ≤ 5.16.0 · ≤ 5.16.0
zoom
rooms
≤ 5.16.0 · ≤ 5.16.0 · ≤ 5.16.0
zoom
virtual desktop infrastructure
≤ 5.14.13 · 5.15.0 — 5.15.11
zoom
zoom
≤ 5.16.0 · ≤ 5.16.0 · ≤ 5.16.0

Mitigating Controls

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-287

Detects unauthorized successful logons resulting from improper authentication implementations.

addresses: CWE-287

Documented procedures ensure personnel are trained on authentication mechanisms, tangibly lowering the risk of improper authentication being exploited.

addresses: CWE-287

Security awareness training instructs users on secure authentication practices and avoiding credential compromise.

addresses: CWE-287

Training on authentication mechanisms and best practices decreases the occurrence of improper authentication.

addresses: CWE-287

Non-repudiation requires strong authentication mechanisms to irrefutably attribute performed actions to specific individuals or processes.

addresses: CWE-287

Session content review can reveal authentication bypasses or failures in session establishment.

addresses: CWE-287

Review of authentication-related audit records can detect improper authentication mechanisms or bypasses.

addresses: CWE-287

Assessments check authentication mechanisms for correct implementation and effectiveness, reducing successful authentication bypass attempts.

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 partial match
blocks

Defining, enforcing, and reviewing access permissions directly addresses the missing authorization checks for custom URL scheme handlers.

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.

blocks

A.5.15 only requires defining a topic-specific access control policy and determining requirements; it does not itself enforce authorization decisions or stop the custom URL scheme handler from being invoked by unauthorized actors.

blocks

Mandating segregated approval and oversight for non-human identities reduces the chance that weak or orphaned credentials can be exploited for unauthorized authentication.

blocks

A.5.17 directly mandates generation of non-guessable unique secrets, secure transmission, immediate change of defaults/temporary creds, strong password enforcement, no-reuse, and compromise response, which stops most improper-authentication exploits at source; the bounded remainder is non-password authentication methods and sufficiency-of-proof cases (e.g. IA-2/IA-5 enhancements) left to other controls.

removes

A.5.18 governs the provisioning, review, and revocation of access rights for authenticated identities; it does not remove the specific code-level flaw in a custom URL scheme handler that fails to restrict invoking actors.

removes

A.8.2 controls allocation/review/expiry of privileged rights via authorization and policy; it does not remove the specific authorization flaw inside a custom-URL-scheme handler (a first-party code defect).

Hardening callouts derived

DISA STIG baselines are authored against specific weaknesses. Where this CVE cites a broad weakness class, the mapping is not asserted at that abstraction (owner ruling, 2026-09-25: grade only at Base and below), so no rule is shown here rather than a rule shown against the wrong grain.

  • No fine-grained STIG row for CWE-287, a class-level weakness. Rules are authored against its narrower children: CWE-295, CWE-306.

References