Bug 2560179 (CVE-2026-115776)

Summary:	CVE-2026-115776 twisted: Twisted: Denial of Service via unbounded IRC buffer
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	unspecified	CC:	dschmidt, eglynn, ikhan, jjoyce, jlanda, jpretori, jschluet, jwong, kshier, lhh, mburns, mgarciac, omaciel, rbobbitt, simaishi, stcannon, ttakamiy, yguenane
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
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Doc Text:	A flaw was found in Twisted. The Internet Relay Chat (IRC) protocol implementation does not enforce a maximum line length when buffering incoming connection data. An unauthenticated remote attacker can exploit this by sending a continuous stream of data without line feed characters to an IRC service. This causes the server process to consume excessive memory until it runs out of resources, resulting in a Denial of Service (DoS) that terminates connections for all users.	Story Points:	---
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-10-23 20:31:47 UTC

Twisted is an event-based framework for internet applications, supporting Python 3.6+. Prior to 26.10.0rc1, twisted.words.protocols.irc.IRC.dataReceived retains all bytes received without a line feed in its per-connection buffer and applies no maximum line length. The twisted.words.service.IRCUser server subclass inherits this behavior, and buffering occurs before PASS, NICK, or USER authentication commands. An unauthenticated connection can continuously grow the buffer until the shared server process runs out of memory and drops all users. This issue is fixed in version 26.10.0rc1.