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CVE-2021-1517· NVD / CVE Program· CNA cisco

Cisco Webex Meetings and Webex Meetings Server Multimedia Sharing Security Bypass Vulnerability

A vulnerability in the multimedia viewer feature of Cisco Webex Meetings and Cisco Webex Meetings Server could allow an authenticated, remote attacker to bypass security protections. This vulnerability is due to unsafe handling of shared content within the multimedia viewer feature. An attacker could exploit this vulnerability by sharing a file through the multimedia viewer feature. A successful exploit could allow the attacker to bypass security protections and prevent warning dialogs from appearing before files are offered to other users.

MediumCVSS 4.3 · v3.1—No exploit No fix recorded
Published
Jun 4, 2021
Updated
Jun 16, 2026
EPSS
0.8% · 56th percentile
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Report tools

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Action score

17

Monitor

Low priority for now.

CVSS
17 / 40 · 4.3 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.8%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
4.3
CNA · cisco
5.0
0.7 point gap

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

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.

We use this product, ask for help

Affected systems

VendorProduct
ciscowebex meetings online
ciscowebex meetings server

Affected versions

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

  • cisco webex meetings online41.3.5
  • cisco webex meetings serverbefore 3.0
  • cisco webex meetings server3.0
  • cisco webex meetings server4.0

Versions reported by the vendor

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

  • Cisco Cisco WebEx Meetings Server

    • n/aaffected

Same product

cisco: all records

Other highest-scoring records for the same primary product.

  • CVE-2018-0287A vulnerability in the Cisco WebEx Network Recording Player for Advanced Recording Format (ARF) files could allow an unauthenticated, remote
    36Monitor
  • CVE-2022-20763Cisco Webex Meetings Java Deserialization Vulnerability
    35Monitor
  • CVE-2018-15422Cisco Webex Network Recording Player Remote Code Execution Vulnerabilities
    32Monitor
  • CVE-2018-15421Cisco Webex Network Recording Player Remote Code Execution Vulnerabilities
    32Monitor
  • CVE-2018-15420Cisco Webex Network Recording Player and Cisco Webex Player Remote Code Execution Vulnerabilities
    32Monitor
  • CVE-2018-15419Cisco Webex Network Recording Player and Cisco Webex Player Remote Code Execution Vulnerabilities
    32Monitor

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.

No nightly-computed relations.

Chain candidates

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

—

Bug bounty scope

No known public program.

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

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

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
low · data or configuration can be modified
Availability
none
Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
Low
Availability impact
None

Weakness class (CWE)

CWE-693 · Protection Mechanism Failure

CVSS vector

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

nvd-primary

Attack context

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

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