CVE-2026-115778Published

Twisted: Unauthenticated Remote Denial of Service in the Twisted conch Telnet Transport via an Unbounded Subnegotiation Buffer

Exact source revision recorded 23 Oct 2026 21:48:20 UTC. It does not establish the source's current position. Latest evidence.

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cve-program · CVE-2026-115778

Published

Twisted is an event-based framework for internet applications, supporting Python 3.6+. Prior to 26.10.0rc1, twisted.conch.telnet.Telnet.dataReceived appends every byte received after IAC SB to a persistent subnegotiation buffer until IAC SE is received, without applying a maximum length. Telnet option negotiation occurs before authentication, so an unauthenticated peer can omit the terminator and continuously grow the buffer. The resulting memory exhaustion can terminate the process and every service it hosts. This issue is fixed in version 26.10.0rc1.

Source published: 23 Oct 2026 20:20:34 UTC
Source modified: 23 Oct 2026 20:55:34 UTC
Observed here: 23 Oct 2026 21:48:20 UTC
Source terms: CVE Program Terms of Use

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CVSS 3.1 · 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H