CVE-2021-22871Network attack vector

Persistent XSS via unsanitized website URL

Published Jan 21, 2021 · Updated Aug 3, 2024

Cross-site scripting in Revive Adserver before 5.1.0 allows remote authenticated users to execute script through a crafted website URL. The affiliate-preview.php tag-generation screen renders the manager-controlled URL website property without HTML escaping, so stored markup executes in another user's browser. A manager account is required to save the payload and a second user must open the preview; the advisory reports limited practical impact because session cookies are not JavaScript-accessible.

CVSS severity3.5
Low
EPSS probability2.12%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Cross-site scripting in Revive Adserver before 5.1.0 allows remote authenticated users to execute script through a crafted website URL. The affiliate-preview.php tag-generation screen renders the manager-controlled URL website property without HTML escaping, so stored markup executes in another user's browser. A manager account is required to save the payload and a second user must open the preview; the advisory reports limited practical impact because session cookies are not JavaScript-accessible.

The record

CVE
CVE-2021-22871
Published
Jan 21, 2021
Updated
Aug 3, 2024
Vendor
Revive Adserver Project
Product
Revive Adserver
Classifications
CWE-79, T1189
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jan 21, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 3, 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=Fixed in 5.1.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Revive Adserver Project · Revive Adserverversion=Fixed in 5.1.0

Published CVSS scores

4.8NVDCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:C/C:L/I:L/A:N
3.5Revive AdserverCVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/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
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1189Drive-by Compromise

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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