Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.12.21, the ip-restriction middleware (hono/ip-restriction) compares incoming IP addresses against configured deny and allow rules using string equality after partial normalization. Non-canonical IPv6 representations of an address already listed in a static rule — such as compressed forms, explicit-zero forms, or hex-notation IPv4-mapped addresses — do not match the normalized rule entry, causing the rule to be silently skipped. This vulnerability is fixed in 4.12.21.

Hono is a Web application framework that provides support for any JavaScript runtime. Prior to 4.12.18, the JSX renderer escapes style attribute object values for HTML but not for CSS. Untrusted input in a style object value or property name can therefore inject additional CSS declarations into the rendered style attribute. The impact is limited to CSS and does not allow JavaScript execution or HTML attribute breakout. This vulnerability is fixed in 4.12.18.

Hono is a web framework written in TypeScript. Prior to version 3.11.7, clients may override named path parameter values from previous requests if the application is using TrieRouter. So, there is a risk that a privileged user may use unintended parameters when deleting REST API resources. TrieRouter is used either explicitly or when the application matches a pattern that is not supported by the default RegExpRouter. Version 3.11.7 includes the change to fix this issue. As a workaround, avoid using TrieRouter directly.

Meshtastic is an open source mesh networking solution. The Meshtastic firmware (starting from version 2.5) introduces asymmetric encryption (PKI) for direct messages, but when the `pki_encrypted` flag is missing, the firmware silently falls back to legacy AES-256-CTR channel encryption. This was an intentional decision to maintain backwards compatibility. However, the end-user applications, like Web app, iOS/Android app, and applications built on top of Meshtastic using the SDK, did not have a way to differentiate between end-to-end encrypted DMs and the legacy DMs. This creates a downgrade attack path where adversaries who know a shared channel key can craft and inject spoofed direct messages that are displayed as if they were PKC encrypted. Users are not given any feedback of whether a direct message was decrypted with PKI or with legacy symmetric encryption, undermining the expected security guarantees of the PKI rollout. Version 2.7.15 fixes this issue.

All versions of the package ithewei/libhv are vulnerable to HTTP Response Splitting when untrusted user input is used to build headers values. An attacker can add the \r\n (carriage return line feeds) characters to end the HTTP response headers and inject malicious content, like for example additional headers or new response body, leading to a potential XSS vulnerability.

cpp-httplib version v0.17.3 through v0.18.3 fails to filter CRLF characters ("\r\n") when those are prefixed with a null byte. This enables attackers to exploit CRLF injection that could further lead to HTTP Response Splitting, XSS, and more.

eventsource-encoder encodes events as well-formed EventSource/Server Sent Event (SSE) messages. Prior to 1.0.2, eventsource-encoder does not sanitize the event or id fields of an EventSourceMessage before serializing them. An attacker who controls either field can inject arbitrary Server-Sent Events line terminators (\n, \r, or \r\n) and thereby forge additional SSE fields or entire messages on the stream. This vulnerability is fixed in 1.0.2.

An issue has been discovered in GitLab CE/EE affecting all versions starting from 15.4 before 15.10.8, all versions starting from 15.11 before 15.11.7, all versions starting from 16.0 before 16.0.2. Open redirection was possible via HTTP response splitting in the NPM package API.

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, an attacker who controls the reason parameter when creating a Response may be able to inject extra headers or similar exploits. This issue has been patched in version 3.13.4.

ewe is a Gleam web server. Prior to version 3.0.6, the encode_headers function in src/ewe/internal/encoder.gleam directly interpolates response header keys and values into raw HTTP bytes without validating or stripping CRLF (\r\n) sequences. An application that passes user-controlled data into response headers (e.g., setting a Location redirect header from a request parameter) allows an attacker to inject arbitrary HTTP response content, leading to response splitting, cache poisoning, and possible cross-site scripting. Notably, ewe does validate CRLF in incoming request headers via validate_field_value() in the HTTP/1.1 parser — but provides no equivalent protection for outgoing response headers in the encoder. This issue has been patched in version 3.0.6.

Prior to Apache HTTP Server 2.4.55, a malicious backend can cause the response headers to be truncated early, resulting in some headers being incorporated into the response body. If the later headers have any security purpose, they will not be interpreted by the client.

A vulnerability in Cisco Email Security Appliance (ESA) and Cisco Secure Email and Web Manager could allow an unauthenticated, remote attacker to conduct an HTTP response splitting attack. This vulnerability is due to the failure of the application or its environment to properly sanitize input values. An attacker could exploit this vulnerability by injecting malicious HTTP headers, controlling the response body, or splitting the response into multiple responses.

Meshtastic-Android is an Android application for the mesh radio software Meshtastic. Prior to version 2.5.21, an attacker is able to send an unencrypted direct message to a victim impersonating any other node of the mesh. This message will be displayed in the same chat that the victim normally communicates with the other node and it will appear as using PKC, while it is not. This means that the victim will be provided with a false sense of security due to the green padlock displayed when using PKC and they'll read the attacker's message as legitimate. Version 2.5.21 contains a patch for the issue. It is suggested to implement a stricter control on whether a message has been received using PKC or using the shared Meshtastic channel key. Moreover, instead of showing no green padlock icon in the chat with no PKC, consider using an explicit indicator like, for example, the yellow half-open padlock displayed when in HAM mode. This remediation, however, applies to the client applications rather than the Meshtastic firmware.

Gakido is a Python HTTP client focused on browser impersonation and anti-bot evasion. A vulnerability was discovered in Gakido prior to version 0.1.1 that allowed HTTP header injection through CRLF (Carriage Return Line Feed) sequences in user-supplied header values and names. When making HTTP requests with user-controlled header values containing `\r\n` (CRLF), `\n` (LF), or `\x00` (null byte) characters, an attacker could inject arbitrary HTTP headers into the request. The fix in version 0.1.1 adds a `_sanitize_header()` function that strips `\r`, `\n`, and `\x00` characters from both header names and values before they are included in HTTP requests.

BlackSheep is an asynchronous web framework to build event based web applications with Python. Prior to 2.4.6, the HTTP Client implementation in BlackSheep is vulnerable to CRLF injection. Missing headers validation makes it possible for an attacker to modify the HTTP requests (e.g. insert a new header) or even create a new HTTP request. Exploitation requires developers to pass unsanitized user input directly into headers.The server part is not affected because BlackSheep delegates to an underlying ASGI server handling of response headers. This vulnerability is fixed in 2.4.6.