CVE-2026-3644: Incomplete control character validation in http.cookies
CSIRTS triage
- What
- Incomplete validation of control characters in the http.cookies module.
- Who is affected
- Python applications using the http.cookies module to parse untrusted cookie data.
- Urgency
- Unknown severity; control character injection may lead to HTTP response splitting or header injection depending on downstream use.
- Action
- Update Python to a patched version with complete control character validation in http.cookies.
AI-assisted analysis generated from the source advisory — verify against the original.
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Details
Original advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-3644
Exploitation outlook
EPSS (FIRST.org) estimates each CVE’s probability of exploitation in the next 30 days — here is the CSIRTS.com read on those numbers.
- Low exploitation riskCVE-2026-36440.48% 30-day exploitation probability — currently an unlikely target, but scores change as exploit code circulates. Riskier than 39% of all EPSS-scored CVEs.
Referenced CVEs
| CVE | CSIRTS overview | External |
|---|---|---|
| CVE-2026-3644 | coverage & exploitation status | NVD · CVE.org |
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