CVE-2025-15282

cpython: Header injection via newlines in data URL mediatype in Python

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Severity

Moderate

Red Hat Product Security

4.8

CVSS 3.1

Review impact separately from score.

Published · January 21, 2026

Updated · August 25, 2026

Description

Missing newline filtering has been discovered in Python. User-controlled data URLs parsed by urllib.request.DataHandler allow injecting headers through newlines in the data URL mediatype.

CVSS score applicability

The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.

Mitigation

Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.

CVSS / CWE

CVSS 3.1 · 4.8
CVSS:3.1/AV:N/AC:H/PR:L/UI:R/S:U/C:N/I:H/A:N

CWE-93 · Improper Neutralization of CRLF Sequences ('CRLF Injection')