Advisories for Pypi/Twisted package

An uncontrolled-resource-consumption vulnerability (CWE-400) in the Twisted HTTP/2 server lets any unauthenticated remote client exhaust server CPU over a single connection. A client that sends a request header block with END_STREAM and then immediately resets the stream makes the server route and render the request before it processes the reset. Reset streams are freed and never count against the concurrent-stream limit, and no reset-rate limiter exists, so the pattern can …

twisted.names.dns.DNSDatagramProtocol, the UDP transport used by twisted's DNS client (twisted.names.client.Resolver, createResolver, and anything built on it, including MX lookups in twisted.mail), accepts a DNS response for a pending query solely on the basis of the 16-bit transaction ID matching. It never checks that the response actually originated from the server the query was sent to. Any host that can deliver a UDP packet to the resolver's listening port with the …

An allocation-without-limits vulnerability in the Twisted XML element stream lets any unauthenticated remote peer exhaust server memory over a single stream. When the peer opens a container element and streams child elements without ever closing the container, every element is materialised into an in-memory tree with no limit on depth or child count. An element is released only when its end tag arrives, so a container the attacker never closes …

An unbounded-buffer vulnerability (CWE-770) in the Twisted words IRC server lets any unauthenticated remote client exhaust server memory. twisted.words.protocols.irc.IRC.dataReceived appends every received byte to a per-connection buffer and only removes data at a line feed, with no maximum length. Because IRC is a plain Protocol and not a LineReceiver, one connection that streams bytes without a line feed grows the buffer without bound and drives the whole single-threaded process to …

An allocation-without-limits vulnerability (CWE-770) in the Twisted conch telnet transport lets any unauthenticated remote peer exhaust server memory over a single connection. When the peer opens a telnet subnegotiation with IAC SB and then streams bytes without ever sending the IAC SE terminator, every byte is appended to a per-connection buffer that has no maximum length. The buffer persists across reads and is released only on the terminator the attacker …

An incomplete header-value validation (CWE-444) in the Twisted HTTP server lets a bare carriage return or line feed in a header value hide a following header from the parser. twisted.web.http.HTTPChannel.headerReceived rejects a NUL byte in a header value but not a bare CR or LF, even though RFC 9110 section 5.5 requires a recipient to reject all three. Because the channel splits requests only on CRLF, a value carrying a …

An infinite-loop vulnerability (CWE-835) in the Twisted IMAP4 server lets an authenticated client freeze the whole process with one small command. twisted.mail.imap4.parseNestedParens reads an IMAP literal size with int() and never rejects a negative value. A negative size such as {-100} drives the parser cursor negative, and because a negative Python index wraps around the end of the string instead of raising, the scanning loop never terminates. It runs synchronously …

wildcardToRegexp() in twisted/mail/imap4.py converts IMAP LIST/LSUB wildcard patterns to Python regular expressions. It substitutes the two IMAP wildcards (* → (?:.?) and % → (?:(?:[^\/])?)) but passes every other character through unchanged to re.compile(). This means that an authenticated IMAP client can send a quoted pattern string containing arbitrary regex syntax - including catastrophic-backtracking constructs such as (a+)+z. Because Twisted runs a cooperative, single-threaded reactor, a blocking regex match freezes …

A single malformed TCP packet is sufficient to block the Twisted reactor's event loop for several seconds. Because Twisted operates on a single-threaded cooperative multitasking model, this is a common Denial of Service (DoS). The process becomes unable to handle new connections, process I/O, or respond to existing requests, effectively paralyzing the server for the duration of the decompression.

The HTTP 1.0 and 1.1 server provided by twisted.web could process pipelined HTTP requests out-of-order, possibly resulting in information disclosure.

The twisted.web.util.redirectTo function contains an HTML injection vulnerability. If application code allows an attacker to control the redirect URL this vulnerability may result in Reflected Cross-Site Scripting (XSS) in the redirect response HTML body.

Twisted is an event-based framework for internet applications. Prior to version 23.10.0rc1, when sending multiple HTTP requests in one TCP packet, twisted.web will process the requests asynchronously without guaranteeing the response order. If one of the endpoints is controlled by an attacker, the attacker can delay the response on purpose to manipulate the response of the second request when a victim launched two requests using HTTP pipeline. Version 23.10.0rc1 contains …

When the host header does not match a configured host, twisted.web.vhost.NameVirtualHost will return a NoResource resource which renders the Host header unescaped into the 404 response allowing HTML and script injection. Example configuration: from twisted.web.server import Site from twisted.web.vhost import NameVirtualHost from twisted.internet import reactor resource = NameVirtualHost() site = Site(resource) reactor.listenTCP(8080, site) reactor.run() Output: ❯ curl -H"Host:<h1>HELLO THERE</h1>" http://localhost:8080/ <html> <head><title>404 - No Such Resource</title></head> <body> <h1>No Such Resource</h1> …

Improper Neutralization in twisted.

The Twisted Web HTTP 1.1 server, located in the twisted.web.http module, parsed several HTTP request constructs more leniently than permitted by RFC 7230: The Content-Length header value could have a + or - prefix. Illegal characters were permitted in chunked extensions, such as the LF (\n) character. Chunk lengths, which are expressed in hexadecimal format, could have a prefix of 0x. HTTP headers were stripped of all leading and trailing …

Twisted web servers that utilize the optional HTTP/2 support suffer from the following flow-control related vulnerabilities.

The Twisted SSH client and server implementation naively accepted an infinite amount of data for the peer's SSH version identifier. A malicious peer can trivially craft a request that uses all available memory and crash the server, resulting in denial of service. The attack is as simple as nc -rv localhost 22 < /dev/zero.

Cookie and Authorization headers are leaked when following cross-origin redirects in twited.web.client.RedirectAgent and twisted.web.client.BrowserLikeRedirectAgent.

Twisted before 16.3.1 does not attempt to address RFC 3875 section 4.1.18 namespace conflicts and therefore does not protect CGI applications from the presence of untrusted client data in the HTTP_PROXY environment variable, which might allow remote attackers to redirect a CGI application's outbound HTTP traffic to an arbitrary proxy server via a crafted Proxy header in an HTTP request, aka an httpoxy issue.

In Twisted Web before 20.3.0, there was an HTTP request splitting vulnerability. When presented with two content-length headers, it ignored the first header. When the second content-length value was set to zero, the request body was interpreted as a pipelined request.

In Twisted Web through 20.3.0, there was an HTTP request splitting vulnerability. When presented with a content-length and a chunked encoding header, the content-length took precedence and the remainder of the request body was interpreted as a pipelined request.

Python Twisted 14.0.0 trustRoot is not respected in HTTP client

In words.protocols.jabber.xmlstream in Twisted through 19.2.1, XMPP support did not verify certificates when used with TLS, allowing an attacker to MITM connections.

In Twisted before 19.2.1, twisted.web did not validate or sanitize URIs or HTTP methods, allowing an attacker to inject invalid characters such as CRLF.