8.2 CVE-2025-14523

A flaw in libsoup’s HTTP header handling allows multiple Host: headers in a request and returns the last occurrence for server-side processing. Common front proxies often honor the first Host: header, so this mismatch can cause vhost confusion where a proxy routes a request to one backend but the backend interprets it as destined for another host. This discrepancy enables request-smuggling style attacks, cache poisoning, or bypassing host-based access controls when an attacker supplies duplicate Host headers.
https://nvd.nist.gov/vuln/detail/CVE-2025-14523

Categories

CWE-444 : Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
The product acts as an intermediary HTTP agent(such as a proxy or firewall) in the data flow between twoentities such as a client and server, but it does notinterpret malformed HTTP requests or responses in ways thatare consistent with how the messages will be processed bythose entities that are at the ultimate destination. Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.) Use a web server that employs a strict HTTP parsing procedure, such as Apache [REF-433]. Use only SSL communication. Terminate the client session after each request. Turn all pages to non-cacheable. SSL/TLS-capable proxy allows HTTP smuggling when used in tandem with HTTP/1.0 services, due to inconsistent interpretation and input sanitization of HTTP messages within the body of another message Chain: caching proxy server has improper input validation (CWE-20) of headers, allowing HTTP response smuggling (CWE-444) using an "LF line ending" Node.js platform allows request smuggling via two Transfer-Encoding headers Web servers allow request smuggling via inconsistent HTTP headers. HTTP server allows request smuggling with both a "Transfer-Encoding: chunked" header and a Content-Length header HTTP server allows request smuggling with both a "Transfer-Encoding: chunked" header and a Content-Length header

References

secalert@redhat.com

https://access.redhat.com/security/cve/CVE-2025-14523
https://bugzilla.redhat.com/show_bug.cgi?id=2421349

CPE

cpe	start	end

REMEDIATION

EXPLOITS

Exploit-db.com

id	description	date
No known exploits

POC Github

Url
No known exploits

Other Nist (github, ...)

Url
No known exploits

CAPEC

Common Attack Pattern Enumerations and Classifications

id	description	severity
273	HTTP Response Smuggling Modification/manipulation of HTTP message headers, request-line and body parameters to disrupt and interfere in the interpretation and parsing of HTTP message lengths/boundaries for consecutive HTTP messages by HTTP agents in a HTTP chain or network path. [Survey network to identify target] The adversary performs network reconnaissance by monitoring relevant traffic to identify the network path and parsing of the HTTP messages with the goal of identifying potential targets. [Identify vulnerabilities in targeted HTTP infrastructure and technologies] The adversary sends a variety of benign/ambiguous HTTP requests to observe responses from HTTP infrastructure to intended targets in order to identify differences/discrepancies in the interpretation and parsing of HTTP requests by examining supported HTTP protocol versions, message sizes, and HTTP headers. [Cause differential HTTP responses by experimenting with identified HTTP Response vulnerabilities] The adversary sends maliciously crafted HTTP request to back-end HTTP infrastructure to inject adversary data into HTTP responses (intended for intermediary and/or front-end client/victim HTTP agents communicating with back-end HTTP infrastructure) for the purpose of interfering with the parsing of HTTP response. The intended consequences of the malicious HTTP request and the subsequent adversary injection and manipulation of HTTP responses will be observed to confirm applicability of identified vulnerabilities in the adversary's plan of attack. [Perform HTTP Response Smuggling attack] Using knowledge discovered in the experiment section above, smuggle a message to cause one of the consequences.	High
33	HTTP Request Smuggling Modification/manipulation of HTTP message headers, request-line and body parameters to disrupt and interfere in the interpretation and parsing of HTTP message lengths/boundaries for consecutive HTTP messages by HTTP agents in a HTTP chain or network path. [Survey network to identify target] The adversary performs network reconnaissance by monitoring relevant traffic to identify the network path and parsing of the HTTP messages with the goal of identifying potential targets. [Identify vulnerabilities in targeted HTTP infrastructure and technologies] The adversary sends a variety of benign/ambiguous HTTP requests to observe responses from HTTP infrastructure in order to identify differences/discrepancies in the interpretation and parsing of HTTP requests by examining supported HTTP protocol versions, message sizes, and HTTP headers. [Cause differential HTTP responses by experimenting with identified HTTP Request vulnerabilities] The adversary sends maliciously crafted HTTP requests to interfere with the parsing of intermediary and back-end HTTP infrastructure, followed by normal/benign HTTP request from the adversary or a random user. The intended consequences of the malicious HTTP requests will be observed in the HTTP infrastructure response to the normal/benign HTTP request to confirm applicability of identified vulnerabilities in the adversary's plan of attack. [Perform HTTP Request Smuggling attack] Using knowledge discovered in the experiment section above, smuggle a message to cause one of the consequences.	High

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