Vulnerability · Published Jan 20, 2026 · Assigned by PSF
CVE-2025-15282Header injection via newlines in data URL mediatype
Medium 6.0
In plain English
A medium-severity security flaw in CPython from Python Software Foundation. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 45% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Severity (CVSS 4.0)6.0Medium
Exploit odds (30 days)0.5%top 54.5% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known
Official description
User-controlled data URLs parsed by urllib.request.DataHandler allow injecting headers through newlines in the data URL mediatype.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| AlmaLinux:10 | python-unversioned-command | 3.12.13-2.el10_2 | ALSA-2026:19064 |
| AlmaLinux:10 | python3 | 3.12.13-2.el10_2 | ALSA-2026:19064 |
| AlmaLinux:10 | python3-debug | 3.12.13-2.el10_2 | ALSA-2026:19064 |
| AlmaLinux:10 | python3-devel | 3.12.13-2.el10_2 | ALSA-2026:19064 |
| AlmaLinux:10 | python3-idle | 3.12.13-2.el10_2 | ALSA-2026:19064 |
| AlmaLinux:10 | python3-libs | 3.12.13-2.el10_2 | ALSA-2026:19064 |
| AlmaLinux:10 | python3-test | 3.12.13-2.el10_2 | ALSA-2026:19064 |
| AlmaLinux:10 | python3-tkinter | 3.12.13-2.el10_2 | ALSA-2026:19064 |
| AlmaLinux:8 | python3.12 | 3.12.13-2.el8_10 | ALSA-2026:10950 |
| AlmaLinux:9 | python3.12 | 3.12.13-2.el9_8 | ALSA-2026:19177 |
| AlmaLinux:8 | python3.12-debug | 3.12.13-2.el8_10 | ALSA-2026:10950 |
| AlmaLinux:9 | python3.12-debug | 3.12.13-2.el9_8 | ALSA-2026:19177 |
| AlmaLinux:8 | python3.12-devel | 3.12.13-2.el8_10 | ALSA-2026:10950 |
| AlmaLinux:9 | python3.12-devel | 3.12.13-2.el9_8 | ALSA-2026:19177 |
| AlmaLinux:8 | python3.12-idle | 3.12.13-2.el8_10 | ALSA-2026:10950 |
| AlmaLinux:9 | python3.12-idle | 3.12.13-2.el9_8 | ALSA-2026:19177 |
| AlmaLinux:8 | python3.12-libs | 3.12.13-2.el8_10 | ALSA-2026:10950 |
| AlmaLinux:9 | python3.12-libs | 3.12.13-2.el9_8 | ALSA-2026:19177 |
| AlmaLinux:8 | python3.12-rpm-macros | 3.12.13-2.el8_10 | ALSA-2026:10950 |
| AlmaLinux:8 | python3.12-test | 3.12.13-2.el8_10 | ALSA-2026:10950 |
| AlmaLinux:9 | python3.12-test | 3.12.13-2.el9_8 | ALSA-2026:19177 |
| AlmaLinux:8 | python3.12-tkinter | 3.12.13-2.el8_10 | ALSA-2026:10950 |
| AlmaLinux:9 | python3.12-tkinter | 3.12.13-2.el9_8 | ALSA-2026:19177 |
| Debian:12 | pypy3 | no fix listed | DEBIAN-CVE-2025-15282 |
| Debian:13 | pypy3 | no fix listed | DEBIAN-CVE-2025-15282 |
| Debian:14 | pypy3 | 7.3.21+dfsg-1 | DEBIAN-CVE-2025-15282 |
| Debian:12 | python3.11 | 3.11.2-6+deb12u7 | DEBIAN-CVE-2025-15282 |
| Debian:13 | python3.13 | 3.13.5-2+deb13u1 | DEBIAN-CVE-2025-15282 |
| Debian:14 | python3.14 | 3.14.3-1 | DEBIAN-CVE-2025-15282 |
| Rocky Linux:10 | python3.12 | 0:3.12.13-2.el10_2 | RLSA-2026:19064 |
| Rocky Linux:8 | python3.12 | 0:3.12.13-2.el8_10 | RLSA-2026:10950 |
| Rocky Linux:9 | python3.12 | 0:3.12.13-2.el9_8 | RLSA-2026:19177 |
| Ubuntu:22.04:LTS | python3.10 | 3.10.12-1~22.04.14 | UBUNTU-CVE-2025-15282 |
| Ubuntu:24.04:LTS | python3.12 | 3.12.3-1ubuntu0.11 | UBUNTU-CVE-2025-15282 |
| Ubuntu:25.10 | python3.13 | 3.13.7-1ubuntu0.3 | UBUNTU-CVE-2025-15282 |
| Ubuntu:25.10 | python3.14 | 3.14.0-1ubuntu0.2 | UBUNTU-CVE-2025-15282 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Python Software Foundation | CPython | 0 – before 3.10.203.11.0 – before 3.11.153.12.0 – before 3.12.133.13.0 – before 3.13.123.14.0 – before 3.14.33.15.0a1 – before 3.15.0a6 |
Weakness: CWE-93 · Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:L/SA:N
References
- https://github.com/python/cpython/pull/143926 patch
- https://github.com/python/cpython/issues/143925 issue-tracking
- https://mail.python.org/archives/list/security-announce@python.org/thread/X66HL7SISGJT33J53OHXMZT4DFLMHVKF/ vendor-advisory
- https://github.com/python/cpython/commit/f25509e78e8be6ea73c811ac2b8c928c28841b9f patch
- https://github.com/python/cpython/commit/05356b1cc153108aaf27f3b72ce438af4aa218c0 patch
- https://github.com/python/cpython/commit/34d76b00dabde81a793bd06dd8ecb057838c4b38 patch
- https://github.com/python/cpython/commit/3f396ca9d7bbe2a50ea6b8c9b27c0082884d9f80 patch
- https://github.com/python/cpython/commit/4ed11d3cd288e6b90196a15c5a825a45d318fe47 patch
- https://github.com/python/cpython/commit/a35ca3be5842505dab74dc0b90b89cde0405017a patch