CVE-2026-0865
wsgiref.headers.Headers allows header newline injection
Severity Score
5.9
*CVSS v4
Exploit Likelihood
*EPSS
Affected Versions
*CPE
Public Exploits
0
*Multiple Sources
Exploited in Wild
-
*KEV
Decision
Track
*SSVC
Descriptions
User-controlled header names and values containing newlines can allow injecting HTTP headers.
Denis Ledoux discovered that Python incorrectly parsed email message headers. An attacker could possibly use this issue to inject arbitrary headers into email messages. This issue only affected python3.6, python3.7, python3.8, python3.9, python3.10, python3.11, python3.12, python3.13, and python3.14 packages. Jacob Walls, Shai Berger, and Natalia Bidart discovered that Python inefficiently parsed XML input with quadratic complexity. An attacker could possibly use this issue to cause a denial of service.
*Credits:
Omar M. Hasan
CVSS Scores
Attack Vector
Attack Complexity
Attack Requirements
Privileges Required
User Interaction
System
Vulnerable | Subsequent
Confidentiality
Integrity
Availability
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality
Integrity
Availability
Attack Vector
Attack Complexity
Authentication
Confidentiality
Integrity
Availability
* Common Vulnerability Scoring System
SSVC
- Decision:Track
Exploitation
Automatable
Tech. Impact
* Organization's Worst-case Scenario
Timeline
- 2026-01-12 CVE Reserved
- 2026-01-20 CVE Published
- 2026-03-03 CVE Updated
- 2026-03-29 EPSS Updated
- ---------- Exploited in Wild
- ---------- KEV Due Date
- ---------- First Exploit
CWE
- CWE-74: Improper Neutralization of Special Elements in Output Used by a Downstream Component ('Injection')
CAPEC
References (15)
| URL | Tag | Source |
|---|---|---|
| https://github.com/python/cpython/issues/143916 | Issue Tracking |
| URL | Date | SRC |
|---|
Affected Vendors, Products, and Versions
| Vendor | Product | Version | Other | Status | ||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Vendor | Product | Version | Other | Status | <-- --> | Vendor | Product | Version | Other | Status |
| Python Software Foundation Search vendor "Python Software Foundation" | CPython Search vendor "Python Software Foundation" for product "CPython" | < 3.10.20 Search vendor "Python Software Foundation" for product "CPython" and version " < 3.10.20" | en |
Affected
| ||||||
| Python Software Foundation Search vendor "Python Software Foundation" | CPython Search vendor "Python Software Foundation" for product "CPython" | >= 3.11.0 < 3.11.15 Search vendor "Python Software Foundation" for product "CPython" and version " >= 3.11.0 < 3.11.15" | en |
Affected
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| Python Software Foundation Search vendor "Python Software Foundation" | CPython Search vendor "Python Software Foundation" for product "CPython" | >= 3.12.0 < 3.12.13 Search vendor "Python Software Foundation" for product "CPython" and version " >= 3.12.0 < 3.12.13" | en |
Affected
| ||||||
| Python Software Foundation Search vendor "Python Software Foundation" | CPython Search vendor "Python Software Foundation" for product "CPython" | >= 3.13.0 < 3.13.12 Search vendor "Python Software Foundation" for product "CPython" and version " >= 3.13.0 < 3.13.12" | en |
Affected
| ||||||
| Python Software Foundation Search vendor "Python Software Foundation" | CPython Search vendor "Python Software Foundation" for product "CPython" | >= 3.14.0 < 3.14.3 Search vendor "Python Software Foundation" for product "CPython" and version " >= 3.14.0 < 3.14.3" | en |
Affected
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