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Zoom Workplace EUVDEUVD-2026-98754

| CVE-2026-53420 HIGH
Classic Buffer Overflow (CWE-120)
2026-10-13 Zoom GHSA-v64v-vg73-53qc
8.0
CVSS 3.1 · Vendor: Zoom
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Attack ChainAIDerived

Hypothetical attack flow derived from CVE metadata – not a confirmed exploit chain

  1. Access
    Lure target user to malicious Zoom Phone interaction
  2. Delivery
    Deliver crafted network payload to client
  3. Exploit
    Trigger buffer overflow in Zoom Phone feature
  4. Execution
    Execute attacker-controlled code across scope boundary
  5. Impact
    Escalate privileges / fully compromise client host

Vulnerability Assessment

Weakness
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Buffer copy size validation
MITRE ATT&CK

1 technique across 1 tactic: Execution

The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up.

Exploitation Conditions

Exploitation requires that the target be running a Zoom Workplace client with the Zoom Phone feature in use, and requires user interaction (UI:R) to trigger the crafted input that overflows the buffer. Attack complexity is High (AC:H), indicating conditions outside the attacker's control (e.g., timing, memory layout, or specific feature state) must be met, which materially limits reliable exploitation. The vendor vector indicates some privilege level is needed (PR:L), though the description claims an unauthenticated user - this prerequisite is unverified and should be confirmed with Zoom. These factors - required user interaction, high complexity, and dependence on the Zoom Phone feature being active - significantly constrain real-world exploitation despite network reachability.

Impact

The vendor CVSS 3.1 vector (CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:H, base 8.0) describes a network-reachable buffer overflow that crosses a scope boundary (S:C) and fully compromises confidentiality, integrity and availability, making it a genuinely serious client-side flaw rather than a high-score-but-low-impact issue. However, several real-risk-dampening signals are present: attack complexity is High (AC:H) and user interaction is Required (UI:R), both of which make reliable, at-scale exploitation harder. A direct conflict exists in the source data that MUST be flagged: the description states 'an unauthenticated user' can conduct the attack, yet the CVSS vector encodes PR:L (low privileges required) - these cannot both be true, so the real authentication requirement should be verified against Zoom bulletin ZSB-26020. No EPSS score, no CISA KEV listing, and no public POC were provided in the input, so there is no evidence of active exploitation or available exploit code at this time. Net assessment: a credible, impactful client vulnerability warranting prompt patching for Zoom Phone users, but the AC:H + UI:R constraints and absence of KEV/EPSS/POC signals suggest it is not currently a mass-exploitation emergency.

Exploit ScenarioDerived

An attacker delivers specially crafted network traffic to the Zoom Phone feature of a targeted user's Zoom Workplace client and induces the user to interact with it (UI:R), triggering a buffer overflow (CWE-120). Because exploitation requires high attack complexity (AC:H) and user interaction, a realistic scenario is a targeted lure against a specific user rather than broad opportunistic scanning. No public exploit code was identified in the provided data.

This Week Schedule remediation this week. Why: HIGH severity (CVSS 7.0-8.9).
Patch available 0.3% exploitation probability (EPSS)

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AnalysisAIv1 – Oct 13, 2026

Zoom Workplace clients with the Zoom Phone feature contain a network-reachable buffer overflow (CWE-120) that can lead to privilege escalation and full compromise of confidentiality, integrity, and availability on the targeted client. The CVSS 3.1 vector (AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:H, base 8.0) requires user interaction and high attack complexity, and it indicates low privileges are needed even though the vendor description claims unauthenticated access-this authentication prerequisite is unverified. No public exploit identified at time of analysis.

RemediationAI

Apply the update or mitigations referenced in Zoom security bulletin ZSB-26020 (https://www.zoom.com/en/trust/security-bulletin/zsb-26020); the exact patched version is not specified in the provided intelligence, so consult the advisory for version-specific guidance. Patch availability is not confirmed in the provided data, so treat the vendor bulletin as the primary source of remediation instructions. If the Zoom Phone feature is not required, disable or restrict it within Zoom Workplace client settings, understanding that this may break telephony and calling functionality. Because exploitation requires user interaction (UI:R) and high attack complexity (AC:H), enforce user awareness to avoid interacting with unsolicited or untrusted Zoom Phone content, though this is a soft control with limited reliability. Network detection or segmentation around Zoom Phone traffic may reduce exposure but can affect legitimate calling services.

Affected VersionsENISA

Zoom Workplace 0 <7.2.0

Affected Packages

euvd zoom_workplace fix: 7.2.0

Source: OSV (Open Source Vulnerabilities)

Affects your stack

Affects 1 package in euvd

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

The root cause is a buffer overflow (CWE-120) in the Zoom Phone component of Zoom Workplace clients, where insufficient bounds checking on network-supplied data can corrupt memory and potentially allow an attacker to gain privileges beyond the Zoom client process (scope change S:C). The CPE cpe:2.3:a:zoom_communications:zoom_workplace:*:*:*:*:*:*:*:* indicates all versions of Zoom Workplace are potentially in scope, though the vendor advisory (ZSB-26020) should be consulted for precise affected versions. Exploitation is constrained by High attack complexity (AC:H), which suggests conditions such as memory layout or specific Zoom Phone feature state must align, and by required user interaction (UI:R). The vector also indicates low privileges (PR:L) are needed, conflicting with the description's unauthenticated claim.

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Severity by source

Vendor (Zoom) PRIMARY 8.0 HIGH
AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:H
vuln.today AI 8.0 HIGH

Network-delivered buffer overflow needing user interaction and precise conditions (AC:H, UI:R); PR:L retained per vendor vector despite the description's 'unauthenticated' claim; scope change and full CIA impact reflect code execution crossing a trust boundary.

3.1 AV:N/AC:H/PR:L/UI:R/S:C/C:H/I:H/A:H
4.0 AV:N/AC:H/AT:N/PR:L/UI:P/VC:H/VI:H/VA:H/SC:L/SI:L/SA:L

Primary rating from Vendor (Zoom).

CVSS VectorVendor: Zoom

Attack Vector
Network
Attack Complexity
High
Privileges Required
Low
User Interaction
Required
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

Lifecycle Timeline

2
Patch available
Oct 13, 2026 - 16:18 EUVD
CVE Published
Oct 13, 2026 - 14:22 cve.org
HIGH 8.0

DescriptionCVE.org

Buffer overflow in a Zoom Phone feature of Zoom Workplace Clients may allow an unauthenticated user to conduct a escalation of privilege via network access.

Executive ViewAI

Why It Matters

A high-severity buffer overflow in Zoom Workplace clients that have the Zoom Phone feature enabled could allow an attacker with a foothold on the network to escalate privileges and gain full control of an affected employee's endpoint, compromising the confidentiality, integrity, and availability of data on that device. Because no vendor patch is currently available, Zoom Phone-enabled endpoints remain exposed while the vendor develops a fix. Leadership should care because this affects a widely deployed communications client on the workforce desktop, and remediation depends on interim risk reduction rather than a simple update.

Business Impact: High
Compensating Controls

No vendor-released patch identified at time of analysis. Interim mitigations: restrict network reachability to Zoom Phone-enabled endpoints, temporarily disable or limit the Zoom Phone feature for high-risk user groups, enforce least-privilege on endpoints, maintain EDR monitoring for privilege escalation and anomalous process behavior, and remind users to avoid interacting with unsolicited meeting, call, or file content. Note the CVSS vector indicates low privileges are required (PR:L) and user interaction is required (UI:R); the vendor's claim of unauthenticated access is unverified.

Threat Intelligence Overview

EPSS Score
0.3%
Top 85% exploitable
Prevalence
High
Zoom Workplace is widely deployed enterprise collaboration client software
Data Quality
4 sources
Confidence: Medium

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity HIGH
CISA KEV No
Public POC No
EPSS 0.3%
Patch available Yes
Active threat No
Deciding rule
HIGH severity (CVSS 7.0-8.9)
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision
Scheduled
Exploitation
None
System Exposure· derived
Open
Automatable
No
Human Impact
High
Technical Impact
Total

Priority Score

40
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +40
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Privilege escalation occurs when an attacker leverages flaws in access control mechanisms to gain permissions beyond what they were originally granted.

A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.

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