CVE-2021-21079Network attack vector

Browser script execution via reflected archiveOffset input

Published Mar 12, 2021 · Updated Apr 23, 2025

Reflected XSS in Adobe Connect 11.0.7 and earlier allows remote attackers to execute JavaScript in a victim's browser via archiveOffset. The recording-page handler reflects the archiveOffset request value into browser-rendered content without neutralizing JavaScript-capable input. Exploitation requires a victim to browse a crafted URL, and the resulting script runs only in that victim's browser context.

CVSS severity6.1
Medium
EPSS probability1.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Reflected XSS in Adobe Connect 11.0.7 and earlier allows remote attackers to execute JavaScript in a victim's browser via archiveOffset. The recording-page handler reflects the archiveOffset request value into browser-rendered content without neutralizing JavaScript-capable input. Exploitation requires a victim to browse a crafted URL, and the resulting script runs only in that victim's browser context.

The record

CVE
CVE-2021-21079
Published
Mar 12, 2021
Updated
Apr 23, 2025
Vendor
Adobe
Product
Adobe Connect
Classifications
CWE-79, T1204.001
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 12, 2021CVE publishedPublication date reported by the CVE source.
  2. Apr 23, 2025Record 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=unspecified <=11.0.7
  2. Affected versionversion=unspecified <=None

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Adobe · Adobe Connectversion=unspecified <=11.0.7; version=unspecified <=None

Published CVSS scores

6.1NIST National Vulnerability DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
6.1Adobe Systems IncorporatedCVSS:3.0/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 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')
T1204.001User Execution: Malicious Link

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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