CVE-2025-43859
h11 is a Python implementation of HTTP/1.1. Prior to version 0.16.0, a leniency in h11's parsing of line terminators in chunked-coding message bodies can lead to request smuggling vulnerabilities under certain conditions. This issue has been patched in version 0.16.0. Since exploitation requires the combination of buggy h11 with a buggy (reverse) proxy, fixing either component is sufficient to mitigate this issue.
Published:Apr 24, 2025
Last Modified:Apr 15, 2026
EPS:Apr 24, 2025
EPSS Score:0.00346
CVSS Score:9.1
Affected Products
Vendor
Product
Action
Vendor
Redhat
Product
Ansible Automation Platform
Redhat
Ansible Automation Platform
Vendor
Redhat
Product
Openstack
Redhat
Openstack
Exploits
No exploit reference
Common Weakness Enumeration
Common Attack Pattern Enumeration and Classification (CAPEC)
Related CVEs
Common Vulnerability Scoring System
Attack Vector
Network
Adjacent
Local
Physical
Privileges Required
None
Low
High
User Interaction
None
Required
Scope
Unchanged
Changed
Confidentiality
None
Low
High
Integrity
None
Low
High
Availability
None
Low
High
