CVE-2026-49452Public exploitNetwork attack vector

Server-side requests via unescaped background hint

Published Aug 18, 2026 · Updated Aug 19, 2026

CSS injection in WeasyPrint before 69.0 allows remote attackers to trigger server-side requests and alter rendered styling via crafted HTML. In weasyprint/css/init.py, presentational-hint handling copied background attribute values into background-image declarations and passed them to tinycss2.parse_blocks_contents() without escaping; the 69.0 fix switched these paths to parse_one_declaration() and html.parse_url() so the value remains quoted inside url(). Exposure requires an application to render untrusted HTML with presentational_hints=True, and the consequence is limited to injected CSS and outbound fetches requested by injected url() values.

CVSS severity6.5
Medium
EPSS probability0.27%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

CSS injection in WeasyPrint before 69.0 allows remote attackers to trigger server-side requests and alter rendered styling via crafted HTML. In weasyprint/css/init.py, presentational-hint handling copied background attribute values into background-image declarations and passed them to tinycss2.parse_blocks_contents() without escaping; the 69.0 fix switched these paths to parse_one_declaration() and html.parse_url() so the value remains quoted inside url(). Exposure requires an application to render untrusted HTML with presentational_hints=True, and the consequence is limited to injected CSS and outbound fetches requested by injected url() values.

The record

CVE
CVE-2026-49452
Published
Aug 18, 2026
Updated
Aug 19, 2026
Vendor
Kozea
Product
WeasyPrint
Classifications
CWE-74
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 18, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 19, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 69.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Kozea · WeasyPrintversion=< 69.0

Published CVSS scores

6.5GitHub_MCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-74Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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