The "%xx" URL decoding function in Squid 2.5STABLE4 and earlier allows remote attackers to bypass url_regex ACLs via a URL with a NULL ("%00") character, which causes Squid to use only a portion of the requested URL when comparing it against the access control lists.
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Debian | — | Upgrade squid | Jul 30, 2024 | Mar 15, 2004 |
| Freebsd | — | Upgrade squid | Dec 10, 2025 | Mar 26, 2004 |
| Gentoo Linux | — | Upgrade net-proxy/squid. | Oct 30, 2017 | Mar 15, 2004 |
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