CVE-2026-53413
CVE-2026-53413 — Zoom Clients - Buffer Over-write
Missing bounds check in the annotator function of Zoom Clients allows buffer over-write, which may allow a meeting participant to achieve remote code execution of another participant via network access.
Published Updated Sources: NVD, Zoom Communications (CNA), SOCRadar CTI
Triage
Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.
Exploitation
Reported
not confirmed by CISA
EPSS
6%
ahead of 92% of scored CVEs
CVSS base
8.3
high
CISA SSVC assessment
Three decision points CISA publishes for the CVEs it assesses · SSVC 2.0.3. A stakeholder decision, not a severity score.
Exploitation
None
none · proof-of-concept · active
Automatable
No
can an attacker script all four kill-chain steps
Technical impact
Total
partial · total control of the vulnerable component
Remediation
The vendor's own words where we have them.
Upgrade Zoom Clients to a fixed release. Apply vendor patches per advisory and restrict external exposure of the affected component until patched.
First 24 hours
Ordered from the record's own fields — exposure first, because you cannot patch what you have not found.
- Identify exposed assets running affected vendor/product/version combinations.
- Prioritize based on EPSS, PoC availability, and external exposure.
- Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class.
Affected scope
Vendor, product and version as the advisories word them.
| Vendor | Product | Versions | Status |
|---|---|---|---|
| Zoom Communications | Zoom Clients | see references | Vulnerable |
Attack characteristics
The CVSS vector, decoded. It describes the attack, not your exposure to it.
Availability
High
Confidentiality
High
Integrity
High
Scope
Changed
Attack Complexity
High
Attack Vector
Network
Privileges Req
None
User Interaction
Required
Every base score collected
Sources score independently and disagree; each row says who scored it and under which version.
| Score | Version | Severity | Expl. | Impact | Source |
|---|---|---|---|---|---|
| 8.3 | CVSS 3.1 | high | 1.6 | 6 | zoom.us (CNA), Zoom Communications (CNA) |
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:H
What this weakness leads to
MITRE's own consequences and mitigations for the weakness class — the authority's wording, not guidance derived from the CVSS vector.
CWE-787 · Out-of-bounds Write
- Modify Memory
- DoS: Crash, Exit, or Restart
- Execute Unauthorized Code or Commands::
Mitigation: Use a language that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, many languages that perform their own memory management, such as Java and Perl, are not subject to buffer overflows. Other languages, such as Ada and C#, typically provide overflow protection, but the protection can be disabled by the programmer. Be wary that a language's interface to native code may still be subject to overflows, even if the language itself is theoretically safe.
Weakness & attack patterns
- CWE-787Out-of-bounds Write
Inferred from the weakness class — not observed against this CVE.
Public exploit
Capability, not use: code existing is a different claim from anyone running it.
Repositories
1
Social mentions
Posts naming this CVE. Attention, not evidence of exploitation — it spikes on disclosure and decays whether or not anything is exploited.
🚨 Zoomsday: Critical zero-click RCE in Zoom. CVE-2026-53413 could enable silent device takeover without user interaction, with potential camera/mic surveillance and credential theft. Read more - https://t.co/aQvOj1CXvV #Cybersecurity #Sequretek https://t.co/WdH3xpfhg2
@sequretek_sqtk· Aug 21, 2026
Warning: #Zero-click #RCE in #Zoom clients! CVE-2026-53413 (CVSS 8.3), an out-of-bounds write vulnerability, could let a meeting participant to execute code on another device without a click or download. https://t.co/3JfKnEjyuy #Patch #Patch #Patch
@CCBalert· Aug 20, 2026
Zoom patches "Zoomsday" zero-click RCE that lets any meeting participant hijack others' devices — Zoom released bulletins on August 11 fixing four flaws, led by CVE-2026-53413 (CVSS 8. #CyberSecurity #InfoSec https://t.co/6GOJENRcRf
@JNitterauer· Aug 17, 2026
CyberSec Daily ✓ · 🚨 Critical Update · August 15, 2026 🎯 Zoom users urged to update after high-severity client vulnerabilities Zoom has updated advisories for CVE-2026-53413, CVE-2026-53414 and CVE-2026-53415, covering memory-safety weaknesses in Zoom clients. Security
@XQOPTRX· Aug 15, 2026
Zoom Users: High Severity Vulnerability Requires Immediate Update. A newly disclosed high-severity vulnerability (CVE-2026-53413) could allow a malicious meeting participant to execute code on another participant's device during a Zoom session. https://t.co/XgbkJxt9nE #Helient https://t.co/ioUHjC0eYi
@Helient· Aug 14, 2026
14 more posts on this CVEShowing 5 of 19 · Who is discussing this CVE, and how loudlyUnlock freeDetection
Read off the CVSS vector and the weakness class. Starting points, not rules we have tested.
- Prioritize edge telemetry for network-reachable Zoom Clients.
- Monitor for scanner or exploit-pattern traffic after 1 public PoC repositories were reported.
Timeline
What happened to this CVE, newest first — with the readings a source repeats on a schedule counted underneath rather than listed.
- 2026
Added · CVSS 3.1 8.3 (AV:N)
Aug 28, 2026 · NVD
Initial · CVE published
Aug 11, 2026 · NVD
Source activity
Readings a source repeats on a schedule, counted rather than listed.
- 8×TweetsAug 12, 2026 – Aug 22, 2026 · SOCRadar CTI
- 7×SvrsAug 12, 2026 – Aug 24, 2026 · SOCRadar CTI
- 1×CVE appeared in the Cve Trends.Aug 13, 2026 · SOCRadar CTI
- 1×Github_Repos · Github repository created, HORKimhab/CVE-2026-53413Aug 13, 2026 · SOCRadar CTI
- 1×CVE modified by MITRE: CVSS metrics updated.Aug 11, 2026 · SOCRadar CTI
References
1 on the record
- www.zoom.com/en/trust/security-bulletin/zsb-26015
Vendor Advisory, NIST
Coverage
10 stories from the feeds we poll
Windows Zero-Day Hits Patch Tuesday: 421 CVEs Fixed [2026] - tech-insider.org
tech-insider.org · Aug 22, 2026
17th August – Threat Intelligence Report - Check Point Research
research.checkpoint.com · Aug 17, 2026
Cyber Security Weekly Newsletter – Outlook RCE, Palo Alto, Cisco 0-day and Windows 0-Day Flaws +20 Stories - CyberSecurityNews
cybersecuritynews.com · Aug 16, 2026
Zoom Annotation Issues Could Let a Meeting Member ‘Hijack’ Another Attendee’s Client!
cybernewsgroup.co.uk · Aug 12, 2026
“Zoomsday” flaws could let one Zoom participant attack another
malwarebytes.com · Aug 12, 2026
5 more reports on this CVEShowing 5 of 10 · Vendor research and security press coverageUnlock freeElsewhere on this site
- Zoom Communicationsevery CVE for this vendor
- Memory Corruptionsame class
- CWE-787other pages naming this weakness
Not in any source we poll
Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.
- No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
- No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
- No exploit packet captures, log samples, or incident case IDs supplied.
Answered from this record1
What should defenders know first?
CVE-2026-53413 is Zoom Clients - Buffer Over-write, a high vulnerability affecting Zoom Clients from Zoom Communications. The current evidence does not list it in CISA KEV, and the exploit status is: Exploitation is reported, but no independent confirmation is available in the sources we have. Public exploit evidence is: 1 public PoC repositories reported; 0 marked weaponized in current dataset. The affected-version evidence is listed in the key facts and affected products tables. Defenders should first verify whether exposed or business-critical assets run those versions, then apply vendor patches or mitigations, restrict reachable attack surface, and preserve logs for detection review. CVSS 8.3 describes technical severity, while EPSS 6% helps estimate near-term exploit likelihood; neither replaces asset context. Unknown fields should remain explicit in tickets, and threat actor, IOC, victimology, or payload claims should not be added unless a cited source supports them. Monitor CISA KEV, vendor advisories, NVD changes, public PoC repositories, and internal telemetry for update triggers.