CVE-2026-53413Public exploitNetwork attack vector

Meeting-participant code execution via unchecked annotation length

Published Aug 11, 2026 · Updated Aug 11, 2026

An out-of-bounds write in the Zoom Clients annotator allows remote attackers in a meeting to execute arbitrary code via annotation messages. CAnnoFormatBlock::Deserialize trusts a network-supplied 32-bit character count when copying into fixed 128-byte buffers, causing a stack overflow. Meeting access is sufficient and no victim action is required; successful corruption runs attacker-controlled code with the participant application's privileges.

CVSS severity8.3
High
EPSS probability5.60%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

An out-of-bounds write in the Zoom Clients annotator allows remote attackers in a meeting to execute arbitrary code via annotation messages. CAnnoFormatBlock::Deserialize trusts a network-supplied 32-bit character count when copying into fixed 128-byte buffers, causing a stack overflow. Meeting access is sufficient and no victim action is required; successful corruption runs attacker-controlled code with the participant application's privileges.

The record

CVE
CVE-2026-53413
Published
Aug 11, 2026
Updated
Aug 11, 2026
Vendor
Zoom Video Communications, Inc.
Product
Zoom Clients
Classifications
CWE-787, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 11, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 11, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=see references

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Zoom Video Communications, Inc. · Zoom Clientsversion=see references

Published CVSS scores

8.3Zoom Video Communications, Inc.CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1203Exploitation for Client Execution

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo