CVE-2026-3644
Incomplete control character validation in http.cookies
CVSS Score
0.0
EPSS Score
0.1%
EPSS Percentile
30th
The fix for CVE-2026-0672, which rejected control characters in http.cookies.Morsel, was incomplete. The Morsel.update(), |= operator, and unpickling paths were not patched, allowing control characters to bypass input validation. Additionally, BaseCookie.js_output() lacked the output validation applied to BaseCookie.output().
| Vendor | python software foundation |
| Product | cpython |
| Published | Mar 16, 2026 |
| Last Updated | Apr 7, 2026 |
Stay Ahead of the Next One
Get instant alerts for python software foundation cpython
Be the first to know when new unknown vulnerabilities affecting python software foundation cpython are published — delivered to Slack, Telegram or Discord.
Get Free Alerts →
Free · No credit card · 60 sec setup
Affected Versions
Python Software Foundation / CPython
0 < 3.13.13 3.14.0 < 3.14.4 3.15.0a1 < 3.15.0a8
References
mail.python.org: https://mail.python.org/archives/list/[email protected]/thread/H6CADMBCDRFGWCMOXWUIHFJNV43GABJ7/ github.com: https://github.com/python/cpython/commit/57e88c1cf95e1481b94ae57abe1010469d47a6b4 github.com: https://github.com/python/cpython/issues/145599 github.com: https://github.com/python/cpython/pull/145600 github.com: https://github.com/python/cpython/commit/62ceb396fcbe69da1ded3702de586f4072b590dd github.com: https://github.com/python/cpython/commit/d16ecc6c3626f0e2cc8f08c309c83934e8a979dd
Credits
Stan Ulbrych Stan Ulbrych Victor Stinner Seth Larson 🔍 Vyom Yadav