Description
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.
Published: 2026-10-23
Score: 7.5 High
EPSS: n/a
KEV: No
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Remediation

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Tracking

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-cwm5-jh59-mwxr Twisted: Unauthenticated Remote Denial of Service in the Twisted conch Telnet Transport via an Unbounded Subnegotiation Buffer
History

Fri, 23 Oct 2026 21:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'none', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Fri, 23 Oct 2026 20:30:00 +0000

Type Values Removed Values Added
Description 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.
Title Twisted: Unauthenticated Remote Denial of Service in the Twisted conch Telnet Transport via an Unbounded Subnegotiation Buffer
Weaknesses CWE-400
CWE-770
References
Metrics cvssV3_1

{'score': 7.5, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

Subscriptions

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-10-23T20:55:34.866Z

Reserved: 2026-10-23T13:28:51.847Z

Link: CVE-2026-115778

cve-icon Vulnrichment

Updated: 2026-10-23T20:52:24.913Z

cve-icon NVD

Status : Received

Published: 2026-10-23T21:17:23.320

Modified: 2026-10-23T21:17:23.320

Link: CVE-2026-115778

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

No data.

Weaknesses