Description
ext/filter in PHP 5.2.0, when FILTER_SANITIZE_STRING is used with the FILTER_FLAG_STRIP_LOW flag, does not properly strip HTML tags, which allows remote attackers to conduct cross-site scripting (XSS) attacks via HTML with a '<' character followed by certain whitespace characters, which passes one filter but is collapsed into a valid tag, as demonstrated using %0b.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 5.0 | php5 | 5.2.0-10+lenny1 | DTSA-39-1 |
| Debian 4.0 | php5 | 5.2.0-8+etch3 | DSA-1283-1 |
Advisories 2
- DTSA-39-1 php5 - several vulnerabilities Debian Security (DSA / DLA) · Mar 9, 2026
- DSA-1283-1 php5 Debian Security (DSA / DLA) · Mar 9, 2026
References
- 25056 third-party-advisory
- DSA-1283 vendor-advisory
- 22914 vdb-entry
- 25062 third-party-advisory
- MDKSA-2007:090 vendor-advisory
- http://www.php-security.org/MOPB/MOPB-18-2007.html
- SUSE-SA:2007:032 vendor-advisory