Allocation of Resources Without Limits or Throttling Affecting twisted package, versions [,26.10.0rc1)
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Start learning- Snyk IDSNYK-PYTHON-TWISTED-21692667
- published24 Oct 2026
- disclosed23 Oct 2026
- creditArkadiusz Marta
Introduced: 23 Oct 2026
NewCVE-2026-115778 (opens in a new tab)How to fix?
Upgrade Twisted to version 26.10.0rc1 or higher.
Overview
Twisted is an event-based network programming and multi-protocol integration framework.
Affected versions of this package are vulnerable to Allocation of Resources Without Limits or Throttling via twisted.conch.telnet.Telnet.dataReceived when processing a telnet subnegotiation that is never terminated. An attacker opens a connection, sends the two-byte sequence IAC SB to begin a subnegotiation, then streams an unbounded sequence of bytes without ever sending the IAC SE terminator. Because self.commands accumulates every received byte as a separate element and is only released upon receipt of the terminator the attacker withholds, the per-connection buffer grows without limit for the life of the connection, exhausting server memory.
PoC
On any endpoint that exposes the Twisted telnet transport, such as the Twisted manhole telnet service, open one connection and send the two bytes `IAC SB` (`0xFF 0xFA`), then stream any non-`0xFF` bytes continuously and never send the `IAC SE` terminator (`0xFF 0xF0`). No credentials are required, because option negotiation runs before authentication.
Every byte is appended to the per-connection subnegotiation buffer with no maximum, and the buffer is released only by the terminator the attacker withholds, so it grows for the life of the connection. Because each byte is retained as a separate element the memory consumed is several times the traffic sent, so a modest-bandwidth peer, or several such connections, drives the process to memory exhaustion.
Note: The PoC targets any endpoint exposing the Twisted telnet transport, such as the Twisted manhole telnet service, and notes that no credentials are required because option negotiation runs before authentication.