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CVE-2026-115776

Twisted: Unauthenticated Remote Denial of Service in the Twisted IRC Server via an Unbounded Line Buffer

Published
2026-10-23
Last modified
2026-10-23
CNA
GitHub_M
NVD status
Received
CWE
CWE-400 CWE-770

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CVSS v3.1 (listed by NVD)
7.5
HIGH
Scored by github.com (not yet scored by NVD)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS v4.0 (listed by NVD)
—
Not scored
CVSS (listed by CVE.org)
7.5
HIGH
Scored by CNA (GitHub_M) · v3.1
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS exploit probability
0.7%
Percentile 54.2%
as of 2026-10-24
CISA KEV
—
Not listed

Attack conditions and impact

Derived from the CNA (via NVD) CVSS 3.1 vector
NetworkNo authNo interaction Confidentiality NIntegrity NAvailability H

This vulnerability may be exploitable over the internet without authentication or user interaction.

MetricValueMeaning
Attack vector AVNNetwork
Attack complexity ACLLow (easy)
Privileges required PRNNone
User interaction UINNone
Scope SUUnchanged
Confidentiality CNNone
Integrity INNone
Availability AHHigh
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Description

NVD

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.

CVSS assessments

ProviderVersionScoreVector
NVD / [email protected] (Secondary)3.17.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CNA / GitHub_M3.17.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products and packages

CNA (CVE.org)

VendorProductVersions
twistedtwisted
affected: < 26.10.0rc1

Open-source packages (GitHub Advisory / OSV)

GHSA-53xc-49m8-p798 GHSA HIGH reviewed

Twisted: Unauthenticated Remote Denial of Service in the Twisted IRC Server via an Unbounded Line Buffer

EcosystemPackageAffected versionsFixed in
PyPITwisted<= 26.4.026.10.0rc1

Linux distribution status

Red Hat ↗ important

ReleasePackageStatusFixed version / notes
Red Hat Ansible Automation Platform 2ansible-automation-platform-24/controller-rhel8fix deferred
Red Hat Ansible Automation Platform 2ansible-automation-platform-25/controller-rhel8fix deferred
Red Hat Ansible Automation Platform 2ansible-automation-platform-25/lightspeed-rhel8fix deferred
Red Hat Ansible Automation Platform 2ansible-automation-platform-26/controller-rhel9affected
Red Hat Ansible Automation Platform 2ansible-automation-platform-26/eda-controller-rhel9affected
Red Hat Ansible Automation Platform 2ansible-automation-platform-26/lightspeed-rhel9affected
Red Hat Ansible Automation Platform 2ansible-automation-platform-27/controller-rhel9affected
Red Hat Ansible Automation Platform 2ansible-automation-platform-27/eda-controller-rhel9affected
Red Hat Ansible Automation Platform 2ansible-automation-platform-27/lightspeed-rhel9affected
Red Hat Ansible Automation Platform 2automation-controlleraffected
Red Hat Ansible Automation Platform 2python-twistedfix deferred
Red Hat OpenStack Platform 16.2python-twistedaffected
Red Hat Ansible Automation Platform 2python3.11-twistedaffected
Red Hat Ansible Automation Platform 2python3.12-twistedaffected
Red Hat Ansible Automation Platform 2python3x-twistedfix deferred

Debian ↗

ReleasePackageStatusFixed version / notes
bookwormtwistedopen not yet assigned
forkytwistedopen not yet assigned
sidtwistedopen not yet assigned
trixietwistedopen not yet assigned no-dsa: Minor issue

Ubuntu ↗ Fetching

References (6)