CVE-2026-0865

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{"bugzilla": {"description": "cpython: wsgiref.headers.Headers allows header newline injection in Python", "id": "2431367", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2431367"}, "csaw": false, "cvss3": {"cvss3_base_score": "4.5", "cvss3_scoring_vector": "CVSS:3.1/AV:N/AC:L/PR:H/UI:R/S:U/C:N/I:H/A:N", "status": "draft"}, "cwe": "CWE-74", "details": ["User-controlled header names and values containing newlines can allow injecting HTTP headers."], "mitigation": {"lang": "en:us", "value": "Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability."}, "name": "CVE-2026-0865", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "package_name": "firefox", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "package_name": "python3.12", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Fix deferred", "package_name": "python3.14", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Fix deferred", "package_name": "python", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Fix deferred", "package_name": "firefox", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Fix deferred", "package_name": "python", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Fix deferred", "package_name": "python3", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "firefox", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "python3", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "python3.11", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "python3.12", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "python36:3.6/python36", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Fix deferred", "package_name": "python39-devel:3.9/python39", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "firefox", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "python3.11", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "python3.12", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "python3.14", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Fix deferred", "package_name": "python3.9", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/a:redhat:enterprise_linux_ai:3", "fix_state": "Fix deferred", "package_name": "rhelai3/bootc-aws-cuda-rhel9", "product_name": "Red Hat Enterprise Linux AI (RHEL AI) 3"}, {"cpe": "cpe:/a:redhat:enterprise_linux_ai:3", "fix_state": "Fix deferred", "package_name": "rhelai3/bootc-azure-cuda-rhel9", "product_name": "Red Hat Enterprise Linux AI (RHEL AI) 3"}, {"cpe": "cpe:/a:redhat:enterprise_linux_ai:3", "fix_state": "Fix deferred", "package_name": "rhelai3/bootc-cuda-rhel9", "product_name": "Red Hat Enterprise Linux AI (RHEL AI) 3"}, {"cpe": "cpe:/a:redhat:enterprise_linux_ai:3", "fix_state": "Fix deferred", "package_name": "rhelai3/bootc-gcp-cuda-rhel9", "product_name": "Red Hat Enterprise Linux AI (RHEL AI) 3"}], "public_date": "2026-01-20T21:26:15Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-0865\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-0865\nhttps://github.com/python/cpython/issues/143916\nhttps://github.com/python/cpython/pull/143917\nhttps://mail.python.org/archives/list/security-announce@python.org/thread/BJ6QPHNSHJTS3A7CFV6IBMCAP2DWRVNT/"], "threat_severity": "Moderate"}

{"analysis": {"en": {"generated_at": "2026-04-16T18:01:53.288533+00:00", "value": {"mitigation_remediation": ["Upgrade CPython to the latest stable release that incorporates the wsgiref header sanitization change.", "If an immediate upgrade is not possible, validate and sanitize all incoming HTTP headers for newline characters before they reach the wsgiref module, or handle headers at the application layer to prevent injection.", "Consider disabling or replacing the use of wsgiref.headers in production code, or using a third-party WSGI server with stricter header validation."], "summary": {"action": "Patch", "impact": "Header Injection"}, "threat_synthesis": {"affected_systems": "The vulnerability affects the CPython implementation of the Python Software Foundation. Any deployment that employs the wsgiref.headers class without the patch\u2014primarily Python web servers or applications that use the wsgiref module\u2014is potentially impacted. Affected version details were not disclosed in the provided data.", "description_and_impact": "User-controlled HTTP header names or values that include newline characters can be used to inject additional headers into the response. This header injection vulnerability may enable attackers to modify or add HTTP headers, potentially leading to HTTP response splitting, cache poisoning, or application logic manipulation. The flaw originates from the lack of sanitization in Python's wsgiref.headers module and is classified as a Header Injection weakness (CWE\u201174).", "risk_and_exploitability": "The CVSS score of 5.9 indicates a moderate impact, while an EPSS score of less than 1% suggests a low exploitation probability at this time. The issue does not appear in the CISA KEV catalog, implying no confirmed widespread exploitation. The likely attack vector is remote, via an HTTP request constructed by an attacker that includes newlines in header names or values processed by wsgiref.headers. An attacker could construct such a request to influence the server's response headers before application logic is applied."}}}}, "created": "2026-01-21T11:18:52.024971+00:00", "updated": "2026-04-16T18:15:43.270783+00:00", "vendors": ["python", "python$PRODUCT$cpython"]}