CVE-2026-0672: 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
- 0.4% chance of exploitation in 30 days – higher than 41% 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:L/VI:H/VA:N/SC:N/SI:N/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
Organizations should immediately upgrade to patched CPython versions where control characters in cookie names, values, and parameters are rejected. If upgrading is not immediately feasible, implement strict input validation and sanitization on all cookie data before it reaches the http.cookies.Morsel class. Web application firewalls (WAFs) can be configured to detect and block HTTP requests containing suspicious control characters in cookies. Developers should audit their codebases for direct or indirect use of http.cookies.Morsel and ensure no untrusted input is passed without validation. Additionally, monitoring HTTP response headers for anomalies can help detect attempted exploitation. Security teams should maintain awareness of updates from the Python Software Foundation and apply security patches promptly. Finally, conduct penetration testing focused on HTTP header injection to verify the effectiveness of mitigations.
Description
When using http.cookies.Morsel, user-controlled cookie values and parameters can allow injecting HTTP headers into messages. Patch rejects all control characters within cookie names, values, and parameters.
References
- github.com/python/cpython/pull/143920 (opens in a new tab)
- github.com/python/cpython/issues/143919 (opens in a new tab)
- mail.python.org/archives/list/security-announce@python.org/thread/6VFLQQEIX673KXKFUZXCUNE5AZOGZ45M/ (opens in a new tab)
- github.com/python/cpython/commit/95746b3a13a985787ef53b977129041971ed7f70 (opens in a new tab)
- github.com/python/cpython/commit/712452e6f1d4b9f7f8c4c92ebfcaac1705faa440 (opens in a new tab)
- github.com/python/cpython/commit/62700107418eb2cca3fc88da036a243ea975f172 (opens in a new tab)
- github.com/python/cpython/commit/7852d72b653fea0199acf5fc2a84f6f8b84eba8d (opens in a new tab)
- github.com/python/cpython/commit/918387e4912d12ffc166c8f2a38df92b6ec756ca (opens in a new tab)
- github.com/python/cpython/commit/b1869ff648bbee0717221d09e6deff46617f3e85 (opens in a new tab)