An issue was discovered in lxml before 4.2.5. lxml/html/clean.py in the lxml.html.clean module does not remove javascript: URLs that use escaping, allowing a remote attacker to conduct XSS attacks, as demonstrated by "j a v a s c r i p t:" in Internet Explorer. This is a similar issue to CVE-2014-3146.
CVE-2018-19787
This medium-severity CVE scores 6.1 under NVD CVSS v3. EPSS exploit probability: 2.4%, top 17% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).
- Lower severity and no public exploit yet
A fix is available — apply it.
- CVSS v3
- 6.1
- EG Score
- 6.1(medium)
- EG Risk
- 28(Track)EG Risk 28/100SSVC: Track
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity61% × 45%Exploitation2% × 40%Automatability0% × 15%Action: Routine — remediate on your standard cadence. - EPSS PROB
- 2%
- EPSS %ILE
- 84%
- KEV
- Not listed
Published
December 2, 2018
Last Modified
December 18, 2025
References (10)
- cve@mitrehttps://github.com/lxml/lxml/commit/6be1d081b49c97cfd7b3fbd934a193b668629109
- cve@mitrehttps://lists.debian.org/debian-lts-announce/2018/12/msg00001.html
- cve@mitrehttps://lists.debian.org/debian-lts-announce/2020/11/msg00044.html
- cve@mitrehttps://usn.ubuntu.com/3841-1/
- cve@mitrehttps://usn.ubuntu.com/3841-2/
- af854a3a-2127-422b-91ae-364da2661108https://github.com/lxml/lxml/commit/6be1d081b49c97cfd7b3fbd934a193b668629109
- af854a3a-2127-422b-91ae-364da2661108https://lists.debian.org/debian-lts-announce/2018/12/msg00001.html
- af854a3a-2127-422b-91ae-364da2661108https://lists.debian.org/debian-lts-announce/2020/11/msg00044.html
- af854a3a-2127-422b-91ae-364da2661108https://usn.ubuntu.com/3841-1/
- af854a3a-2127-422b-91ae-364da2661108https://usn.ubuntu.com/3841-2/
Patch Availability(2)
| Vendor / Ecosystem | Fixed in / Patch | Released | Source |
|---|---|---|---|
| ubuntu | python-lxml (2.3.2-1ubuntu0.3) @ precise | 2026-05-28 | ubuntu |
| ubuntu | python3-lxml (3.5.0-1ubuntu0.1) @ xenial | 2026-05-28 | ubuntu |
Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.
Affected Packages
(6 across 6 ecosystems)
Debian:11(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| lxml | — | 4.2.5-1 | — |
Debian:12(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| lxml | — | 4.2.5-1 | — |
Debian:13(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| lxml | — | 4.2.5-1 | — |
Debian:14(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| lxml | — | 4.2.5-1 | — |
Debian:9(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| lxml | 3.7.1-1 | 3.7.1-1+deb9u1 | — |
PyPI(1)
| Package | Vulnerable range | Fixed in | Dependents |
|---|---|---|---|
| lxml | 0.9 ... 4.2.4 (128 versions) | 4.2.5 | — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
All Vendor Advisories
(3)
Every vendor that published an advisory referencing this CVE — pulled from our cve_vendor_advisories aggregation. Click any row for the vendor's original advisory page.
- Microsoft MSRCCVE-2018-197872021-07-30
An issue was discovered in lxml before 4.2.5. lxml/html/clean.py in the lxml.html.clean module does not remove javascript: URLs that use escaping allowing a remote attacker to conduct XSS attacks as demonstrated by "j a v a s c r i p t:" in Internet Explorer. This is a similar issue to CVE-2014-3146.
- UbuntuUSN-3841-1MEDIUM
lxml vulnerability
- UbuntuUSN-3841-2MEDIUM
lxml vulnerability
Data Freshness Timeline
(refreshed 6× in last 7d / 24× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
Showing the most recent 100 of 151 total refreshes for this CVE.
- 2026-09-18 19:22 UTCEPSS rescore
- 2026-09-17 19:22 UTCEPSS rescore
- 2026-09-16 05:06 UTCEPSS rescore
- 2026-09-15 03:05 UTCEPSS rescore
- 2026-09-13 16:42 UTCEPSS rescore
- 2026-09-12 14:56 UTCEPSS rescore
- 2026-09-11 14:47 UTCEPSS rescore
- 2026-09-11 09:32 UTCEPSS rescore
- 2026-09-08 20:34 UTCOSV refresh
- 2026-09-07 15:57 UTCEPSS rescore
- 2026-09-06 13:43 UTCEPSS rescore
- 2026-09-05 15:24 UTCEPSS rescore
- 2026-09-04 13:56 UTCEPSS rescore
- 2026-09-04 05:02 UTCEPSS rescore
- 2026-09-02 14:07 UTCEPSS rescore
- 2026-09-01 13:49 UTCEPSS rescore
- 2026-09-01 03:32 UTCEPSS rescore
- 2026-08-28 21:36 UTCEPSS rescore
- 2026-08-27 14:21 UTCEPSS rescore
- 2026-08-26 14:42 UTCEPSS rescore
- 2026-08-25 13:44 UTCEPSS rescore
- 2026-08-22 05:37 UTCOSV refresh
- 2026-08-21 23:45 UTCEPSS rescore
- 2026-08-20 22:51 UTCEPSS rescore
- 2026-08-19 17:00 UTCEPSS rescore
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- 2026-08-18 13:44 UTCEPSS rescore
- 2026-08-17 13:43 UTCEPSS rescore
- 2026-08-16 14:51 UTCEPSS rescore
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- 2026-08-15 01:26 UTCEPSS rescore
- 2026-08-13 21:56 UTCEPSS rescore
- 2026-08-12 13:46 UTCEPSS rescore
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- 2026-08-08 16:32 UTCEPSS rescore
- 2026-08-07 16:23 UTCEPSS rescore
- 2026-08-06 13:42 UTCEPSS rescore
- 2026-08-06 08:45 UTCOSV refresh
- 2026-08-05 19:13 UTCEPSS rescore
- 2026-08-04 15:05 UTCEPSS rescore
- 2026-08-02 02:23 UTCEPSS rescore
- 2026-08-01 04:12 UTCEPSS rescore
- 2026-07-30 16:24 UTCEPSS rescore
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- 2026-07-28 15:32 UTCEPSS rescore
- 2026-07-26 14:51 UTCEPSS rescore
- 2026-07-26 14:51 UTCEPSS rescore
- 2026-07-25 14:14 UTCEPSS rescore
- 2026-07-24 14:14 UTCEPSS rescore
- 2026-07-24 14:14 UTCEPSS rescore
- 2026-07-23 14:15 UTCEPSS rescore
- 2026-07-23 01:35 UTCEG score recompute
- 2026-07-22 22:15 UTCEG score recompute
- 2026-07-22 14:05 UTCEPSS rescore
- 2026-07-21 15:22 UTCEPSS rescore
- 2026-07-21 02:17 UTCOSV refresh
- 2026-07-20 17:04 UTCEPSS rescore
- 2026-07-20 17:04 UTCEPSS rescore
- 2026-07-19 14:28 UTCEPSS rescore
- 2026-07-19 02:26 UTCEPSS rescore
- 2026-07-19 02:26 UTCEPSS rescore
- 2026-07-16 16:59 UTCEPSS rescore
- 2026-07-16 16:59 UTCEPSS rescore
- 2026-07-15 16:55 UTCEPSS rescore
- 2026-07-15 16:55 UTCEPSS rescore
- 2026-07-15 01:56 UTCEPSS rescore
- 2026-07-15 01:56 UTCEPSS rescore
- 2026-07-13 22:27 UTCEPSS rescore
- 2026-07-13 22:26 UTCEPSS rescore
- 2026-07-13 06:10 UTCEPSS rescore
- 2026-07-12 05:43 UTCEPSS rescore
- 2026-07-11 08:24 UTCEPSS rescore
- 2026-07-09 19:06 UTCEPSS rescore
- 2026-07-08 15:11 UTCEPSS rescore
- 2026-07-07 13:42 UTCEPSS rescore
- 2026-07-07 13:42 UTCEPSS rescore
- 2026-07-06 16:24 UTCEPSS rescore
- 2026-07-06 16:24 UTCEPSS rescore
- 2026-07-06 02:20 UTCEPSS rescore
- 2026-07-05 02:27 UTCEPSS rescore
- 2026-07-04 06:28 UTCEPSS rescore
- 2026-07-04 06:28 UTCEPSS rescore
- 2026-07-03 21:26 UTCOSV refresh
- 2026-07-02 16:54 UTCEPSS rescore
- 2026-07-01 15:03 UTCEPSS rescore
- 2026-07-01 15:03 UTCEPSS rescore
- 2026-06-30 23:20 UTCEPSS rescore
- 2026-06-30 23:19 UTCEPSS rescore
- 2026-06-29 14:03 UTCEPSS rescore
- 2026-06-28 14:04 UTCEPSS rescore
- 2026-06-28 04:53 UTCEPSS rescore
- 2026-06-28 04:53 UTCEPSS rescore
- 2026-06-27 03:06 UTCEPSS rescore
- 2026-06-27 03:06 UTCEPSS rescore
- 2026-06-25 13:47 UTCEPSS rescore
- 2026-06-25 13:47 UTCEPSS rescore
- 2026-06-24 14:02 UTCEPSS rescore
- 2026-06-24 14:02 UTCEPSS rescore
- 2026-06-23 21:30 UTCEPSS rescore
- 2026-06-23 21:30 UTCEPSS rescore
- 2026-06-23 21:30 UTCEPSS rescore
Frequently asked(5)
What is CVE-2018-19787?
When was CVE-2018-19787 disclosed?
Is CVE-2018-19787 actively exploited?
What is the CVSS score of CVE-2018-19787?
How do I remediate CVE-2018-19787?
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2018-19787
Is Your Infrastructure Affected by CVE-2018-19787?
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