CVE-2025-15282: Python Software Foundation CPython · CWE-93
Affects Python Software Foundation CPythonSource CVE Database V5
Not known to be exploited · CVSS 6.0 Medium · fixed in 3.15.0a6 : update Python Software Foundation CPython when convenient.
Data as of 26 Oct 2026, 06:26 UTC
- EPSS
- 0.5% chance of exploitation in 30 days – higher than 44% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 3.15.0a6, 3.14.3, 3.13.12 +3
CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:L/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 20 Jan 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 2026-10-26.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| Python Software FoundationCPython | Affected
| Fixed in
|
PyPIcpythonpkg:pypi/cpythonOther threats | Affected
| Fixed in– |
GitHubCPythonpkg:github/CPythonOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
If you cannot patch yet, organizations should implement strict input validation and sanitization on any user-supplied data URLs processed by urllib.request.DataHandler. Specifically, reject or sanitize newline (CRLF) characters in the media type portion of data URLs to prevent header injection. Review and harden any code that constructs or parses data URLs, ensuring that untrusted input cannot influence HTTP headers. Employ web application firewalls (WAFs) or intrusion detection systems (IDS) to detect and block suspicious HTTP header injection attempts. Monitor Python Software Foundation announcements and promptly apply security updates once patches addressing CVE-2025-15282 are available. Consider isolating or sandboxing components that process untrusted URLs to limit the impact of potential exploitation. Additionally, conduct code audits and penetration testing focused on HTTP header injection vectors in applications using affected Python versions. Educate developers about the risks of improper input handling in URL parsing to prevent similar vulnerabilities.
Description
User-controlled data URLs parsed by urllib.request.DataHandler allow injecting headers through newlines in the data URL mediatype.
References
- github.com/python/cpython/pull/143926 (opens in a new tab)
- github.com/python/cpython/issues/143925 (opens in a new tab)
- mail.python.org/archives/list/security-announce@python.org/thread/X66HL7SISGJT33J53OHXMZT4DFLMHVKF/ (opens in a new tab)
- github.com/python/cpython/commit/f25509e78e8be6ea73c811ac2b8c928c28841b9f (opens in a new tab)
- github.com/python/cpython/commit/05356b1cc153108aaf27f3b72ce438af4aa218c0 (opens in a new tab)
- github.com/python/cpython/commit/34d76b00dabde81a793bd06dd8ecb057838c4b38 (opens in a new tab)
- github.com/python/cpython/commit/3f396ca9d7bbe2a50ea6b8c9b27c0082884d9f80 (opens in a new tab)
- github.com/python/cpython/commit/4ed11d3cd288e6b90196a15c5a825a45d318fe47 (opens in a new tab)
- github.com/python/cpython/commit/a35ca3be5842505dab74dc0b90b89cde0405017a (opens in a new tab)