CVE-2021-39205Network attack vector

Client-side script execution via unsafe config parsing

Published Sep 15, 2021 · Updated Aug 4, 2024

Prototype pollution in Jitsi Meet before 2.0.6173 allows remote attackers to execute client-side scripts through crafted URL config parameters. The config-parameter parser copied attacker-supplied property paths into nested JSON objects without rejecting prototype-chain keys or checking every path segment. A victim must open a crafted meeting URL; the resulting prototype modification can drive DOM-based XSS or spoof page content in that browser.

CVSS severity6.1
Medium
EPSS probability1.23%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Prototype pollution in Jitsi Meet before 2.0.6173 allows remote attackers to execute client-side scripts through crafted URL config parameters. The config-parameter parser copied attacker-supplied property paths into nested JSON objects without rejecting prototype-chain keys or checking every path segment. A victim must open a crafted meeting URL; the resulting prototype modification can drive DOM-based XSS or spoof page content in that browser.

The record

CVE
CVE-2021-39205
Published
Sep 15, 2021
Updated
Aug 4, 2024
Vendor
Jitsi
Product
Jitsi Meet
Classifications
CWE-79, CWE-1321, T1204.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Sep 15, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

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

  1. Affected versionversion=< 2.0.6173

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Jitsi · Jitsi Meetversion=< 2.0.6173

Published CVSS scores

4.3NIST NVDAV:N/AC:M/Au:N/C:N/I:P/A:N
6.1NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

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 exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CWE-1321Improperly Controlled Modification of Object Prototype Attributes ('Prototype Pollution')
T1204.001User Execution: Malicious Link

Public exploit references

No public exploit references are available in this record.

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

Technologies

Your stack

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Your stack

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