CVE-2025-15282
published 2026-01-20CVE-2025-15282: User-controlled data URLs parsed by urllib.request.DataHandler allow injecting headers through newlines in the data URL mediatype.
PriorityP336medium6CVSS 4.0
AVNACLATPPRLUINVCNVIHVANSCNSILSANEXCRXIRXARXMAVXMACXMATXMPRXMUIXMVCXMVIXMVAXMSCXMSIXMSAXSXAUXRXVXREXUX
EPSS
0.48%
38.1th percentile
User-controlled data URLs parsed by urllib.request.DataHandler allow injecting headers through newlines in the data URL mediatype.
Affected
12 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| debian | pypy3 | < python3.13 3.13.12-1 (forky) | python3.13 3.13.12-1 (forky) |
| debian | python2.7 | < python3.13 3.13.12-1 (forky) | python3.13 3.13.12-1 (forky) |
| debian | python3.11 | < python3.13 3.13.12-1 (forky) | python3.13 3.13.12-1 (forky) |
| debian | python3.13 | < python3.13 3.13.12-1 (forky) | python3.13 3.13.12-1 (forky) |
| debian | python3.14 | < python3.13 3.13.12-1 (forky) | python3.13 3.13.12-1 (forky) |
| debian | python3.9 | < python3.13 3.13.12-1 (forky) | python3.13 3.13.12-1 (forky) |
| python_software_foundation | cpython | < 3.10.20 | 3.10.20 |
| python_software_foundation | cpython | >= 3.11.0 < 3.11.15 | 3.11.15 |
| python_software_foundation | cpython | >= 3.12.0 < 3.12.13 | 3.12.13 |
| python_software_foundation | cpython | >= 3.13.0 < 3.13.12 | 3.13.12 |
| python_software_foundation | cpython | >= 3.14.0 < 3.14.3 | 3.14.3 |
| python_software_foundation | cpython | >= 3.15.0a1 < 3.15.0a6 | 3.15.0a6 |
CVSS provenance
nvdv4.06.0MEDIUMCVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
osv6.0MEDIUM
vendor_debian6.0MEDIUM
vendor_redhat6.0MEDIUM
vendor_ubuntu5.3MEDIUM
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OSV
python2.7 vulnerabilities
osv·2026-03-19·CVSS 5.7
CVE-2025-12084 [MEDIUM] python2.7 vulnerabilities
python2.7 vulnerabilities
USN-8018-1 fixed CVE-2025-12084, CVE-2025-15282, CVE-2026-0672,
CVE-2026-0865 for python3. This update provides the corresponding updates
for python2.7.
Original advisory details:
Denis Ledoux discovered that Python incorrectly parsed email message
headers. An attacker could possibly use this issue to inject arbitrary
headers into email messages. This issue only affected python3.6,
python3.7, python3.8, python3.9, python3.10, python3.11, python3.12,
python3.13, and python3.14 packages. (CVE-2025-11468)
Jacob Walls, Shai Berger, and Natalia Bidart discovered that Python
inefficiently parsed XML input with quadratic complexity. An attacker
could possibly use this issue to cause a denial of service.
(CVE-2025-12084)
It was discovered that Python incorrectly pars
OSV
python3.4, python3.5, python3.6, python3.7, python3.8, python3.9,
python3.10, python3.11, python3.12, python3.13, python3.14 regression
osv·2026-03-09·CVSS 5.7
CVE-2025-15366 [MEDIUM] python3.4, python3.5, python3.6, python3.7, python3.8, python3.9,
python3.10, python3.11, python3.12, python3.13, python3.14 regression
python3.4, python3.5, python3.6, python3.7, python3.8, python3.9,
python3.10, python3.11, python3.12, python3.13, python3.14 regression
USN-8018-1 fixed vulnerabilities in python3. That update introduced
regressions. The patches for CVE-2025-15366 and CVE-2025-15367 caused
behavior regressions in IMAP and POP3 handling, which upstream chose to
avoid by not backporting them. Additionally, the patch for CVE-2026-0865
incorrectly rejected horizontal tabs in wsgiref headers. This update fixes
these problems.
We apologize for the inconvenience.
Original advisory details:
Denis Ledoux discovered that Python incorrectly parsed email message
headers. An attacker could possibly use this issue to inject arbitrary
headers into email messages. This issue only affected python3.6,
python3.7, python3
OSV
python3.14, python3.13, python3.12, python3.11, python3.10, python3.9,
python3.8, python3.7, python3.6, python3.5, python3.4 vulnerabilities
osv·2026-02-05·CVSS 5.7
CVE-2025-11468 [MEDIUM] python3.14, python3.13, python3.12, python3.11, python3.10, python3.9,
python3.8, python3.7, python3.6, python3.5, python3.4 vulnerabilities
python3.14, python3.13, python3.12, python3.11, python3.10, python3.9,
python3.8, python3.7, python3.6, python3.5, python3.4 vulnerabilities
Denis Ledoux discovered that Python incorrectly parsed email message
headers. An attacker could possibly use this issue to inject arbitrary
headers into email messages. This issue only affected python3.6, python3.7,
python3.8, python3.9, python3.10, python3.11, python3.12, python3.13, and
python3.14 packages. (CVE-2025-11468)
Jacob Walls, Shai Berger, and Natalia Bidart discovered that Python
inefficiently parsed XML input with quadratic complexity. An attacker could
possibly use this issue to cause a denial of service. (CVE-2025-12084)
It was discovered that Python incorrectly parsed malicious plist files. An
attacker could possibly use this issue
GHSA
GHSA-6rv6-r2f2-gqrc: User-controlled data URLs parsed by urllib
ghsa_unreviewed·2026-01-21
CVE-2025-15282 [MEDIUM] CWE-93 GHSA-6rv6-r2f2-gqrc: User-controlled data URLs parsed by urllib
User-controlled data URLs parsed by urllib.request.DataHandler allow injecting headers through newlines in the data URL mediatype.
OSV
CVE-2025-15282: User-controlled data URLs parsed by urllib
osv·2026-01-20·CVSS 6.0
CVE-2025-15282 [MEDIUM] CVE-2025-15282: User-controlled data URLs parsed by urllib
User-controlled data URLs parsed by urllib.request.DataHandler allow injecting headers through newlines in the data URL mediatype.
Ubuntu
Python 2.7 vulnerabilities
vendor_ubuntu·2026-03-19·CVSS 5.3
CVE-2025-12084 [MEDIUM] Python 2.7 vulnerabilities
Title: Python 2.7 vulnerabilities
Summary: Several security issues were fixed in python2.7
USN-8018-1 fixed CVE-2025-12084, CVE-2025-15282, CVE-2026-0672,
CVE-2026-0865 for python3. This update provides the corresponding updates
for python2.7.
Original advisory details:
Denis Ledoux discovered that Python incorrectly parsed email message
headers. An attacker could possibly use this issue to inject arbitrary
headers into email messages. This issue only affected python3.6,
python3.7, python3.8, python3.9, python3.10, python3.11, python3.12,
python3.13, and python3.14 packages. (CVE-2025-11468)
Jacob Walls, Shai Berger, and Natalia Bidart discovered that Python
inefficiently parsed XML input with quadratic complexity. An attacker
could possibly use this issue to cause a denial of service
Ubuntu
Python regression
vendor_ubuntu·2026-03-09·CVSS 5.3
CVE-2025-15367 [MEDIUM] Python regression
Title: Python regression
Summary: USN-8018-1 introduced a regression in Python
USN-8018-1 fixed vulnerabilities in python3. That update introduced
regressions. The patches for CVE-2025-15366 and CVE-2025-15367 caused
behavior regressions in IMAP and POP3 handling, which upstream chose to
avoid by not backporting them. Additionally, the patch for CVE-2026-0865
incorrectly rejected horizontal tabs in wsgiref headers. This update fixes
these problems.
We apologize for the inconvenience.
Original advisory details:
Denis Ledoux discovered that Python incorrectly parsed email message
headers. An attacker could possibly use this issue to inject arbitrary
headers into email messages. This issue only affected python3.6,
python3.7, python3.8, python3.9, python3.10, python3.11, python3.12,
pytho
Ubuntu
Python vulnerabilities
vendor_ubuntu·2026-02-05·CVSS 5.3
CVE-2025-15366 [MEDIUM] Python vulnerabilities
Title: Python vulnerabilities
Summary: Several security issues were fixed in Python.
Denis Ledoux discovered that Python incorrectly parsed email message
headers. An attacker could possibly use this issue to inject arbitrary
headers into email messages. This issue only affected python3.6, python3.7,
python3.8, python3.9, python3.10, python3.11, python3.12, python3.13, and
python3.14 packages. (CVE-2025-11468)
Jacob Walls, Shai Berger, and Natalia Bidart discovered that Python
inefficiently parsed XML input with quadratic complexity. An attacker could
possibly use this issue to cause a denial of service. (CVE-2025-12084)
It was discovered that Python incorrectly parsed malicious plist files. An
attacker could possibly use this issue to cause Python to use excessive
resources, leading to
Red Hat
cpython: Header injection via newlines in data URL mediatype in Python
vendor_redhat·2026-01-20·CVSS 6.0
CVE-2025-15282 [MEDIUM] CWE-93 cpython: Header injection via newlines in data URL mediatype in Python
cpython: Header injection via newlines in data URL mediatype in Python
User-controlled data URLs parsed by urllib.request.DataHandler allow injecting headers through newlines in the data URL mediatype.
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.
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.
Package: firefox (Red Hat Enterprise Linux 10) - Fix deferred
Package: python3.12 (Red Hat Enterprise Linux 10) - Fix deferred
Package: python3.14 (Red Hat En
Debian
CVE-2025-15282: pypy3 - User-controlled data URLs parsed by urllib.request.DataHandler allow injecting h...
vendor_debian·2025·CVSS 6.0
CVE-2025-15282 [MEDIUM] CVE-2025-15282: pypy3 - User-controlled data URLs parsed by urllib.request.DataHandler allow injecting h...
User-controlled data URLs parsed by urllib.request.DataHandler allow injecting headers through newlines in the data URL mediatype.
Scope: local
bookworm: open
bullseye: open
forky: open
sid: open
trixie: open
No detection rules found.
No public exploits indexed.
Bugzilla
CVE-2025-15282 python3.9: Header injection via newlines in data URL mediatype in Python [fedora-all]
bugzilla·2026-01-21·CVSS 6.0
CVE-2025-15282 [MEDIUM] CVE-2025-15282 python3.9: Header injection via newlines in data URL mediatype in Python [fedora-all]
CVE-2025-15282 python3.9: Header injection via newlines in data URL mediatype in Python [fedora-all]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
Discussion:
We're not going to proactively fix this in EOL Pythons in Fedora to keep them as close as possible to their EL clones.
---
*** Bug 2431831 has been marked as a duplicate of this bug. ***
Bugzilla
CVE-2025-15282 asahi-installer: Header injection via newlines in data URL mediatype in Python [fedora-42]
bugzilla·2026-01-21·CVSS 6.0
CVE-2025-15282 [MEDIUM] CVE-2025-15282 asahi-installer: Header injection via newlines in data URL mediatype in Python [fedora-42]
CVE-2025-15282 asahi-installer: Header injection via newlines in data URL mediatype in Python [fedora-42]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
Discussion:
This message is a reminder that Fedora Linux 42 is nearing its end of life.
Fedora will stop maintaining and issuing updates for Fedora Linux 42 on 2026-05-13.
It is Fedora's policy to close all bug reports from releases that are no longer
maintained. At that time this bug will be closed as EOL if it remains open with a
'version' of '42'.
Package Maintainer: If you wish for this bug to remain open because you
plan to fix it in a currently maintained
Bugzilla
CVE-2025-15282 python3.6: Header injection via newlines in data URL mediatype in Python [fedora-42]
bugzilla·2026-01-21·CVSS 6.0
CVE-2025-15282 [MEDIUM] CVE-2025-15282 python3.6: Header injection via newlines in data URL mediatype in Python [fedora-42]
CVE-2025-15282 python3.6: Header injection via newlines in data URL mediatype in Python [fedora-42]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
Discussion:
We're not going to proactively fix this in EOL Pythons in Fedora to keep them as close as possible to their EL clones.
---
This message is a reminder that Fedora Linux 42 is nearing its end of life.
Fedora will stop maintaining and issuing updates for Fedora Linux 42 on 2026-05-13.
It is Fedora's policy to close all bug reports from releases that are no longer
maintained. At that time this bug will be closed as EOL if it remains open with a
'version' of '
Bugzilla
CVE-2025-15282 python3.9: Header injection via newlines in data URL mediatype in Python [fedora-42]
bugzilla·2026-01-21·CVSS 6.0
CVE-2025-15282 [MEDIUM] CVE-2025-15282 python3.9: Header injection via newlines in data URL mediatype in Python [fedora-42]
CVE-2025-15282 python3.9: Header injection via newlines in data URL mediatype in Python [fedora-42]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
Discussion:
We're not going to proactively fix this in EOL Pythons in Fedora to keep them as close as possible to their EL clones.
---
*** This bug has been marked as a duplicate of bug 2431854 ***
Bugzilla
CVE-2025-15282 cpython: Header injection via newlines in data URL mediatype in Python
bugzilla·2026-01-20·CVSS 6.0
CVE-2025-15282 [MEDIUM] CVE-2025-15282 cpython: Header injection via newlines in data URL mediatype in Python
CVE-2025-15282 cpython: Header injection via newlines in data URL mediatype in Python
User-controlled data URLs parsed by urllib.request.DataHandler allow injecting headers through newlines in the data URL mediatype.
Wiz
CVE-2025-15282 Impact, Exploitability, and Mitigation Steps | Wiz
blogs_wiz·CVSS 2.0
CVE-2025-15282 [LOW] CVE-2025-15282 Impact, Exploitability, and Mitigation Steps | Wiz
## CVE-2025-15282 :
Python Interpreter vulnerability analysis and mitigation
User-controlled data URLs parsed by urllib.request.DataHandler allow injecting headers through newlines in the data URL mediatype.
Source : NVD
## 6
Score
Published January 20, 2026
Severity MEDIUM
CNA Score 6.0
Affected Technologies
Python Interpreter
Wolfi
Has Public Exploit No
Has CISA KEV Exploit No
CISA KEV Release Date N/A
CISA KEV Due Date N/A
Exploitation Probability Percentile (EPSS) 13.5
Exploitation Probability (EPSS) N/A
Affected packages and libraries
libpython3_13t1_0
python313-curses
Sources
NVD
Chainguard Has Fix Added at: Jan 28, 2026
Debian 11 Severity MEDIUM Has Fix Added at: Jan 23, 2026
Debian 12, 13 Severity MEDIUM No Fix Added at: Jan 23, 2026
Debian 14 Has Fix Ad
https://github.com/python/cpython/commit/05356b1cc153108aaf27f3b72ce438af4aa218c0https://github.com/python/cpython/commit/34d76b00dabde81a793bd06dd8ecb057838c4b38https://github.com/python/cpython/commit/3f396ca9d7bbe2a50ea6b8c9b27c0082884d9f80https://github.com/python/cpython/commit/4ed11d3cd288e6b90196a15c5a825a45d318fe47https://github.com/python/cpython/commit/a35ca3be5842505dab74dc0b90b89cde0405017ahttps://github.com/python/cpython/commit/f25509e78e8be6ea73c811ac2b8c928c28841b9fhttps://github.com/python/cpython/issues/143925https://github.com/python/cpython/pull/143926https://mail.python.org/archives/list/[email protected]/thread/X66HL7SISGJT33J53OHXMZT4DFLMHVKF/
2026-01-20
Published