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Fencer Intel
medium 6.1

CVE-2014-3146 json

lxml Cross-site Scripting Via Control Characters

published 2014-05-14 12 y ago modified 2026-06-17 4 mo ago also GHSA-57qw-cc2g-pv5p , PYSEC-2014-9 , EUVD-2014-0033

cvss
6.1
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
6.3%
EPSS 6.3% chance of exploitation in 30 days, percentile 93%
public exploits
1
Exploit-DB

Summary

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.

Patch / fix

  • pypi lxml 3.3.5
  • lxml Debian 14, Debian 13, Debian 12 3.3.5-1

debian advisories DEBIAN-CVE-2014-3146

  • lxml Ubuntu 14.04 LTS 3.3.3-1ubuntu0.1

ubuntu advisories UBUNTU-CVE-2014-3146

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2014-3146 updated cvss 2.6

python-lxml: clean_html input sanitization flaw

  • Red Hat Enterprise Linux 5 python-lxml Red Hat Enterprise Linux 6 python-lxml Red Hat Enterprise Linux 7 python-lxml
    affected: no fix planned “Will not fix”

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Timeline

  1. First public exploit (EDB-39155)
  2. Published

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
10 mo ago

Exploit prediction

6.33% chance of exploitation in the next 30 days, higher than 93% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

  • EDB-39155 lxml - 'clean_html' Security Bypass remote, 2014-04-15
  • mailman-mail5.webfaction.com https://mailman-mail5.webfaction.com/pipermail/lxml/2014-April/007128.html referenced PoC, tagged "exploit" by a source, unverified
  • securityfocus.com http://www.securityfocus.com/bid/67159 referenced PoC, tagged "exploit" by a source, unverified
  • seclists.org http://seclists.org/fulldisclosure/2014/Apr/319 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CISA ADP 3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
CNA 3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
NVD 2.0 4.3 AV:N/AC:M/Au:N/C:N/I:P/A:N
GitHub 3.1 6.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

Affected packages

ecosystem package affected fixed in
pypi lxml
<3.3.5
3.3.5

Classification

Weakness
  • CWE-79 Improper Neutralization of Input During Web Page Generation

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.