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CVE-2023-49646· NVD / CVE Program· CNA Zoom

Improper authentication in some Zoom clients before version 5.16.5 may allow an authenticated user to conduct a denial of service via networ

Improper authentication in some Zoom clients before version 5.16.5 may allow an authenticated user to conduct a denial of service via network access.

MediumCVSS 6.5 · v3.1—No exploit No fix recorded
Published
Dec 13, 2023
Updated
Jun 17, 2026
EPSS
0.4% · 32th percentile
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Report tools

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Action score

26

Monitor

Low priority for now.

CVSS
26 / 40 · 6.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.4%

CNA vs NVD score

NVD
6.5
CNA · Zoom
6.4
0.1 point gap

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:L

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Noroxi analysis

No Noroxi analysis for this record yet

We don't hand-write analysis for the hundreds of thousands of vulnerabilities in the database; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.

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Affected systems

VendorProduct
zoommeeting software development kit
zoomvideo software development kit
zoomvirtual desktop infrastructure
zoomzoom

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • zoom meeting software development kitbefore 5.16.5
  • zoom video software development kitbefore 5.16.5
  • zoom virtual desktop infrastructurebefore 5.14.14
  • zoom virtual desktop infrastructure5.15.0 and later · before 5.15.12
  • zoom zoombefore 5.16.5

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Zoom). Independent of NVD's CPE analysis and usually ahead of it.

  • Zoom Video Communications, Inc. Zoom Clients

    • See referencesaffected

Same product

zoom: all records

Other highest-scoring records for the same primary product.

  • CVE-2024-24691Zoom Desktop Client for Windows, Zoom VDI Client for Windows, and Zoom Meeting SDK for Windows - Improper Input Validation
    40Plan
  • CVE-2025-62484Zoom Workplace Clients - Inefficient Regular Expression Complexity
    39Monitor
  • CVE-2025-64741Zoom Workplace for Android - Improper Authorization Handling
    39Monitor
  • CVE-2025-0147Zoom Workplace App for Linux - Type Confusion
    39Monitor
  • CVE-2025-49457Zoom Clients for Windows - Untrusted Search Path
    35Monitor
  • CVE-2025-27440Zoom Apps - Heap-based Buffer Overflow
    35Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

—

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

  • CVE-2023-435860 days apartPath traversal in Zoom Desktop Client for Windows, Zoom VDI Client for Windows, and Zoom SDKs for Windows may allow an authenticated user to
    35Monitor

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-347 · Improper Verification of Cryptographic Signature

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

nvd-primary

Root cause

The verifier takes the algorithm to verify with from the token’s own header. Untrusted data ends up deciding its own verification rule.

The bug in code

The whole CWE-347 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

ts
const claims = jwt.verify(token, publicKey);

Fixed

ts
const claims = jwt.verify(token, publicKey, {  algorithms: ["RS256"],  issuer: "https://id.example.com",  audience: "portal",});

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

ATT&CK techniques

—

Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records