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5.9
MEDIUM CVSS 4.0
CVE-2026-0865
wsgiref.headers.Headers allows header newline injection
Description

User-controlled header names and values containing newlines can allow injecting HTTP headers.

INFO

Published Date :

Jan. 20, 2026, 10:15 p.m.

Last Modified :

Jan. 20, 2026, 11:16 p.m.

Remotely Exploit :

Yes !

Source :

[email protected]
Affected Products

The following products are affected by CVE-2026-0865 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

No affected product recoded yet

: Total Affected Vendor : 0 | Products : 0
CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 4.0 MEDIUM 28c92f92-d60d-412d-b760-e73465c3df22
CVSS 4.0 MEDIUM [email protected]
Solution
Sanitize user-controlled HTTP headers to prevent injection of newline characters and unintended headers.
  • Validate and sanitize all user-supplied header names and values.
  • Disallow newline characters in HTTP headers.
  • Implement strict input validation for HTTP headers.
  • Reject requests with invalid header formats.
References to Advisories, Solutions, and Tools

Here, you will find a curated list of external links that provide in-depth information, practical solutions, and valuable tools related to CVE-2026-0865.

URL Resource
https://github.com/python/cpython/commit/22e4d55285cee52bc4dbe061324e5f30bd4dee58
https://github.com/python/cpython/commit/23e3c0ae867cca0130e441e776c9955b9027c510
https://github.com/python/cpython/commit/2f840249550e082dc351743f474ba56da10478d2
https://github.com/python/cpython/commit/4802b96a2cde58570c24c13ef3289490980961c5
https://github.com/python/cpython/commit/e4846a93ac07a8ae9aa18203af0dd13d6e7a6995
https://github.com/python/cpython/commit/f7fceed79ca1bceae8dbe5ba5bc8928564da7211
https://github.com/python/cpython/issues/143916
https://github.com/python/cpython/pull/143917
https://mail.python.org/archives/list/[email protected]/thread/BJ6QPHNSHJTS3A7CFV6IBMCAP2DWRVNT/
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-0865 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-0865 weaknesses.

CAPEC-3: Using Leading 'Ghost' Character Sequences to Bypass Input Filters Using Leading 'Ghost' Character Sequences to Bypass Input Filters CAPEC-6: Argument Injection Argument Injection CAPEC-7: Blind SQL Injection Blind SQL Injection CAPEC-8: Buffer Overflow in an API Call Buffer Overflow in an API Call CAPEC-9: Buffer Overflow in Local Command-Line Utilities Buffer Overflow in Local Command-Line Utilities CAPEC-10: Buffer Overflow via Environment Variables Buffer Overflow via Environment Variables CAPEC-13: Subverting Environment Variable Values Subverting Environment Variable Values CAPEC-14: Client-side Injection-induced Buffer Overflow Client-side Injection-induced Buffer Overflow CAPEC-24: Filter Failure through Buffer Overflow Filter Failure through Buffer Overflow CAPEC-28: Fuzzing Fuzzing CAPEC-34: HTTP Response Splitting HTTP Response Splitting CAPEC-42: MIME Conversion MIME Conversion CAPEC-43: Exploiting Multiple Input Interpretation Layers Exploiting Multiple Input Interpretation Layers CAPEC-45: Buffer Overflow via Symbolic Links Buffer Overflow via Symbolic Links CAPEC-46: Overflow Variables and Tags Overflow Variables and Tags CAPEC-47: Buffer Overflow via Parameter Expansion Buffer Overflow via Parameter Expansion CAPEC-51: Poison Web Service Registry Poison Web Service Registry CAPEC-52: Embedding NULL Bytes Embedding NULL Bytes CAPEC-53: Postfix, Null Terminate, and Backslash Postfix, Null Terminate, and Backslash CAPEC-64: Using Slashes and URL Encoding Combined to Bypass Validation Logic Using Slashes and URL Encoding Combined to Bypass Validation Logic CAPEC-67: String Format Overflow in syslog() String Format Overflow in syslog() CAPEC-71: Using Unicode Encoding to Bypass Validation Logic Using Unicode Encoding to Bypass Validation Logic CAPEC-72: URL Encoding URL Encoding CAPEC-76: Manipulating Web Input to File System Calls Manipulating Web Input to File System Calls CAPEC-78: Using Escaped Slashes in Alternate Encoding Using Escaped Slashes in Alternate Encoding CAPEC-79: Using Slashes in Alternate Encoding Using Slashes in Alternate Encoding CAPEC-80: Using UTF-8 Encoding to Bypass Validation Logic Using UTF-8 Encoding to Bypass Validation Logic CAPEC-83: XPath Injection XPath Injection CAPEC-84: XQuery Injection XQuery Injection CAPEC-101: Server Side Include (SSI) Injection Server Side Include (SSI) Injection CAPEC-105: HTTP Request Splitting HTTP Request Splitting CAPEC-108: Command Line Execution through SQL Injection Command Line Execution through SQL Injection CAPEC-120: Double Encoding Double Encoding CAPEC-135: Format String Injection Format String Injection CAPEC-250: XML Injection XML Injection CAPEC-267: Leverage Alternate Encoding Leverage Alternate Encoding CAPEC-273: HTTP Response Smuggling HTTP Response Smuggling

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-0865 vulnerability anywhere in the article.

Results are limited to the first 20 news articles due to potential performance issues.

The following table lists the changes that have been made to the CVE-2026-0865 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • CVE Modified by [email protected]

    Jan. 20, 2026

    Action Type Old Value New Value
    Added Reference https://github.com/python/cpython/commit/22e4d55285cee52bc4dbe061324e5f30bd4dee58
    Added Reference https://github.com/python/cpython/commit/23e3c0ae867cca0130e441e776c9955b9027c510
    Added Reference https://github.com/python/cpython/commit/2f840249550e082dc351743f474ba56da10478d2
    Added Reference https://github.com/python/cpython/commit/4802b96a2cde58570c24c13ef3289490980961c5
    Added Reference https://github.com/python/cpython/commit/e4846a93ac07a8ae9aa18203af0dd13d6e7a6995
    Added Reference https://github.com/python/cpython/commit/f7fceed79ca1bceae8dbe5ba5bc8928564da7211
  • New CVE Received by [email protected]

    Jan. 20, 2026

    Action Type Old Value New Value
    Added Description User-controlled header names and values containing newlines can allow injecting HTTP headers.
    Added CVSS V4.0 AV:N/AC:L/AT:P/PR:H/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
    Added CWE CWE-74
    Added Reference https://github.com/python/cpython/issues/143916
    Added Reference https://github.com/python/cpython/pull/143917
    Added Reference https://mail.python.org/archives/list/[email protected]/thread/BJ6QPHNSHJTS3A7CFV6IBMCAP2DWRVNT/
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
Vulnerability Scoring Details
Base CVSS Score: 5.9
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