CVE-2026-28348 | lxml_html_clean: CSS @import Filter Bypass via Unicode Escapes

Exp

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.

Published: 2026-03-05 Last update: 2026-03-09 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-28348 is rated Exploit Available (50/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.05%). 1 public exploit reference(s) are indexed (Exploit-DB). Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2026-28348

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2026-28348

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-05-12 0.03% 0.05% +0.02%
2 2026-03-06 — 0.03% —

Full EPSS history (2 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-28348

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.1 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:N)
Service keeps running; no real outage angle.
 2.8 2.7 [email protected]

Weakness enumeration for CVE-2026-28348

GitHub Security Advisory for CVE-2026-28348

GHSA-hw26-mmpg-fqfg · Severity: medium · Ecosystem: pip — lxml-html-clean has CSS @import Filter Bypass via Unicode Escapes

OS Trackers for CVE-2026-28348

vendor priority summary link
alpine — CVE-2026-28348: 1 source package rows (py3-lxml-html-clean); 4 state rows across 2 repos (3.23-community, edge-community); fixed 0, open 4. https://security.alpinelinux.org/vuln/CVE-2026-28348
debian not yet assigned CVE-2026-28348 not yet assigned priority: Debian including 1 source packages (lxml-html-clean), 3 status rows across 3 suites (forky, sid, trixie): resolved 2, open 1. https://security-tracker.debian.org/tracker/CVE-2026-28348
ubuntu medium CVE-2026-28348 medium priority: Ubuntu including 1 source packages (lxml-html-clean), 4 status rows across 4 suites (jammy, noble, questing, upstream): needs-triage 3, DNE 1. https://ubuntu.com/security/CVE-2026-28348

Affected software / configurations for CVE-2026-28348

Vendor Product Version Raw CPE
fedoralovespython lxml_html_clean < 0.4.4 cpe:2.3:a:fedoralovespython:lxml_html_clean:*:*:*:*:*:python:*:*

References for CVE-2026-28348

cvelogic Threat Intelligence