Lab: Web cache poisoning to exploit a DOM vulnerability via a cache with strict cacheability criteria
Summary: This PortSwigger lab presents a DOM-based vulnerability that can be exploited through web cache poisoning, in which a user visits the home page roughly once a minute. The lab's cache applies stricter criteria for deciding which responses are cacheable, so the cache behavior must be studied closely, and the goal is to poison the cache with a response that executes alert(document.cookie) in the visitor's browser.
Why it matters: A DOM flaw that looks minor on its own becomes a persistent attack against every visitor once a poisoned response is cached, and this lab's stricter cacheability criteria show that the caching layer itself decides whether that happens.
Read the original at PortSwigger Research ↗
- Topics
- Vulnerabilities & Patching
- Related
- Attackers Exploit UnrealIRCd Flaw That Enables Server-Level Command Injection Cyber Risks · Nov 14, 2026U.S. CISA adds Check Point and UnrealIRCd flaws to its Known Exploited Vulnerabilities catalog Cyber Risks · Nov 14, 2026PostgreSQL Patches 52 Flaws, Including 22-Year-Old Bug Enabling Authenticated RCE Cyber Risks · Nov 13, 2026