CVE-2025-6442
BaseFortify
Publication date: 2025-06-25
Last updated on: 2025-08-18
Assigner: Zero Day Initiative
Description
Description
CVSS Scores
EPSS Scores
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Meta Information
Affected Vendors & Products
| Vendor | Product | Version / Range |
|---|---|---|
| ruby-lang | webrick | to 1.8.2 (exc) |
Helpful Resources
Exploitability
| CWE ID | Description |
|---|---|
| CWE-444 | The product acts as an intermediary HTTP agent (such as a proxy or firewall) in the data flow between two entities such as a client and server, but it does not interpret malformed HTTP requests or responses in ways that are consistent with how the messages will be processed by those entities that are at the ultimate destination. |
Attack-Flow Graph
AI Powered Q&A
Can you explain this vulnerability to me?
CVE-2025-6442 is a vulnerability in Ruby's WEBrick HTTP server, specifically in the read_headers method. It arises from inconsistent parsing of HTTP header terminators, allowing remote attackers to perform HTTP request smuggling. This means an attacker can send crafted HTTP requests that are interpreted differently by the proxy and the server, enabling them to smuggle arbitrary HTTP requests through the server when it is deployed behind an HTTP proxy that meets certain conditions. [1]
How can this vulnerability impact me? :
This vulnerability can impact you by allowing an attacker to smuggle arbitrary HTTP requests, which can lead to a high integrity impact, meaning attackers could potentially manipulate or inject unauthorized requests. The confidentiality impact is low, and there is no impact on availability. Essentially, it could allow attackers to bypass security controls or perform unauthorized actions by exploiting the inconsistent parsing of HTTP headers. [1]
How can this vulnerability be detected on my network or system? Can you suggest some commands?
This vulnerability can be detected by monitoring HTTP traffic for inconsistent or malformed HTTP header terminators, specifically looking for requests that do not use proper CRLF (`\r\n`) line endings as required by RFC standards. You can capture and analyze HTTP requests using tools like tcpdump or Wireshark to inspect header line endings. For example, use tcpdump to capture HTTP traffic: `tcpdump -i <interface> -s 0 -w capture.pcap port 80` and then analyze the capture in Wireshark to check for headers ending with LF only or containing bare CR or NUL characters. Additionally, testing with crafted HTTP requests that use improper line endings (LF only or bare CR) against the WEBrick server can help detect if the server is vulnerable. [2]
What immediate steps should I take to mitigate this vulnerability?
The immediate mitigation step is to update Ruby WEBrick to the latest version that includes the security fix enforcing strict HTTP request formatting compliance as per RFC standards. This update requires that HTTP request lines and headers use CRLF (`\r\n`) line endings exclusively and disallows bare CR, LF, and NUL characters in headers, preventing HTTP request smuggling attacks. If updating is not immediately possible, consider deploying additional HTTP proxy or firewall rules to detect and block malformed HTTP requests that do not conform to proper CRLF line endings. [1, 2]