Collected research

CORS vulnerabilities: Weaponizing permissive CORS configurations

Exploiting trust: Weaponizing permissive CORS configurations

Thomas Stacey · Outpost24 · 1 October 2024

A scan of every domain in a managed pentest estate for permissive Cross-Origin Resource Sharing, followed by exploitation, argues such findings are routinely under-rated. The article classifies the origin-validation errors seen: unconditional reflection of Origin, trusting the null origin a sandboxed iframe can send, prefix matching on the trusted domain or localhost, and blanket subdomain trust. Case studies reach session theft and account takeover.

Record

Document

Exploiting trust: Weaponizing permissive CORS configurations

Researcher

Thomas Stacey

Published by

Outpost24

Date

1 October 2024

Topic

Other

In the archive

• Collected in the 2024 research round

Related sources

• Outpost24 CORS Check extension

Tags

• cors
• same-origin-policy
• url-parsing
• filter-bypass
• info-leak
• case-study
• large-scale-scan
• owasp-a01-2021
• owasp-a05-2021

This page is the archive's own catalogue record. The research is the work of Thomas Stacey, first published at the original source. Preserved copies are kept so the citation survives its host; this one was last captured on 9 August 2026.