6.1

CVE-2026-28348: fedora-python lxml_html_clean Improper Encoding or Escaping of Output

CVSS: 6.1v3.1MediumAnalyzed
AliasesGHSA-hw26-mmpg-fqfgPYSEC-2026-2201UBUNTU-CVE-2026-28348
Published 05-03-2026Last modified 06-03-2026
Open JSON

Vulnerability summary

CVE-2026-28348 is a medium (CVSS 6.1) Improper Encoding or Escaping of Output vulnerability in fedora-python lxml_html_clean. EPSS estimates a 0.29% chance of exploitation in the next 30 days, higher than 20.3% of scored vulnerabilities. 1 public exploit is recorded.

Overall risk
34/100
0100
Medium · default modelHow is this calculated?
CVSS score
6.1/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.29%
0%100%
Low · +0.06 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits1github

Advisory lineage

Upstream 0 · Downstream 2 · Related 3
OPENSUSE-SU-2026:10322-1OPENSUSE-SU-2026:20345-1CGA-75RJ-3CGF-PF8F

Timeline

  1. 05-03-2026
    PublishedVulnerability first disclosed.
  2. 06-03-2026
    Last modifiedVulnerability information updated.

Description

lxml_html_clean is a project for HTML cleaning functionalities copied from `lxml.html.clean`. Prior to version 0.4.4, the _has_sneaky_javascript() method strips backslashes before checking for dangerous CSS keywords. This causes CSS Unicode escape sequences to bypass the @import and expression() filters, allowing external CSS loading or XSS in older browsers. This issue has been patched in version 0.4.4.

CVSS metrics

6 scores · 6 sources · 1 version

EPSS trend

Probability

0.29%

Chance of exploitation in the next 30 days

Percentile

20%

Versus all other CVEs

30-day change

+0.06 pp

From 0.23% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.29%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

1 found
  • githubUnverified

    Lxml Html Clean

    Maturity: poc

Weaknesses

CWE · root cause

Affected systems

Debian2 products
  • lxml< 4.9.2-1+deb12u1 | < 5.2.0-1
  • lxml-html-clean< 0.4.4-1~deb13u1 | < 0.4.4-1
Chainguard1 product
  • label-studio< 1.22.0-r7
Fedora-python1 product
Fedoralovespython1 product
PyPI1 product
  • lxml-html-clean< 0.4.4
Ubuntu1 product
  • lxml-html-cleanAll versions (No fix recorded)

6 vendors · 7 products

References

8 links