CVE-2014-3146 — Incomplete blacklist vulnerability in the lxml

Incomplete blacklist vulnerability in the lxml.html.clean module in lxml before 3.3.5 allows remote attackers to conduct cross-site scripting (XSS) attacks via control characters in the link scheme to the clean_html function.

01What is this vulnerability?

Incomplete blacklist vulnerability in the lxml.html.clean module in lxml before 3.3.5 allows remote attackers to conduct cross-site scripting (XSS) attacks via control characters in the link scheme to the clean_html function.

02Affected products

Vendor	Product	Versions
n	a / n/a	n/a

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2014-05-14T19:00:00.000Z
• Last modified: 2025-12-17T21:03:02.761Z

09References

• www.debian.org — http://www.debian.org/security/2014/dsa-2941
• lxml.de — http://lxml.de/3.3/changes-3.3.5.html
• www.openwall.com — http://www.openwall.com/lists/oss-security/2014/05/09/7
• www.ubuntu.com — http://www.ubuntu.com/usn/USN-2217-1
• mailman-mail5.webfaction.com — https://mailman-mail5.webfaction.com/pipermail/lxml/2014-April/007128.html
• secunia.com — http://secunia.com/advisories/58744
• advisories.mageia.org — http://advisories.mageia.org/MGASA-2014-0218.html
• www.securityfocus.com — http://www.securityfocus.com/bid/67159
• www.mandriva.com — http://www.mandriva.com/security/advisories?name=MDVSA-2015:112
• secunia.com — http://secunia.com/advisories/58013
• seclists.org — http://seclists.org/fulldisclosure/2014/Apr/210
• secunia.com — http://secunia.com/advisories/59008
• lists.opensuse.org — http://lists.opensuse.org/opensuse-updates/2014-05/msg00083.html
• seclists.org — http://seclists.org/fulldisclosure/2014/Apr/319