Bug 2436315 (CVE-2026-1801)

Summary: CVE-2026-1801 libsoup: libsoup: HTTP Request Smuggling via malformed chunk headers
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
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Priority: low    
Version: unspecifiedKeywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in libsoup, an HTTP client/server library. This HTTP Request Smuggling vulnerability arises from non-RFC-compliant parsing in the soup_filter_input_stream_read_line() logic, where libsoup accepts malformed chunk headers, such as lone line feed (LF) characters instead of the required carriage return and line feed (CRLF). A remote attacker can exploit this without authentication or user interaction by sending specially crafted chunked requests. This allows libsoup to parse and process multiple HTTP requests from a single network message, potentially leading to information disclosure.
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Bug Depends On: 2436316, 2436318, 2436317    
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Description OSIDB Bzimport 2026-02-03 12:46:34 UTC 
HTTP Request Smuggling vulnerability in the chunked transfer encoding parser of the libsoup HTTP library. The flaw is caused by non-RFC-compliant parsing in the soup_filter_input_stream_read_line() logic, where libsoup accepts lone LF (\n) characters and other malformed chunk headers instead of enforcing CRLF (\r\n) as required by RFC 9112. When a malicious HTTP client sends specially crafted chunked requests, libsoup may parse and process multiple HTTP requests from a single network message. Although exploitation is possible remotely without authentication or user interaction, the impact is limited because SoupServer is not commonly used in internet-facing infrastructure.