CVE-2026-115774

Twisted: Denial of Service in the Twisted IMAP4 Server via a Negative Literal Size in SEARCH

Published Oct 23, 2026 CVSS 3.1 · 4.9 Medium EPSS < 1% KEV · Not listed
Description
Twisted is an event-based framework for internet applications, supporting Python 3.6+. Prior to 26.10.0rc1, twisted.mail.imap4.IMAP4Server reaches twisted.mail.imap4.parseNestedParens with a negative literal size in an authenticated SEARCH command after the client enters the selected mailbox state. The negative size moves the parser cursor below zero, and Python's negative indexing prevents the synchronous scanning loop from terminating. The loop freezes the single-threaded reactor, stopping other IMAP connections and any SMTP or POP3 services hosted in the same process until restart. This issue is fixed in version 26.10.0rc1.

Remediation

No solution or workaround provided in the CVE record

Tracking

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Advisories

Source ID Title
Github GHSA Github GHSA GHSA-2qrf-pqgx-qh9v Twisted: Denial of Service in the Twisted IMAP4 Server via a Negative Literal Size in SEARCH
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}

Type Values Removed Values Added
First Time appeared Twisted
Twisted twisted
Vendors & Products Twisted
Twisted twisted
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.mail.imap4.IMAP4Server reaches twisted.mail.imap4.parseNestedParens with a negative literal size in an authenticated SEARCH command after the client enters the selected mailbox state. The negative size moves the parser cursor below zero, and Python's negative indexing prevents the synchronous scanning loop from terminating. The loop freezes the single-threaded reactor, stopping other IMAP connections and any SMTP or POP3 services hosted in the same process until restart. This issue is fixed in version 26.10.0rc1.
Title Twisted: Denial of Service in the Twisted IMAP4 Server via a Negative Literal Size in SEARCH
Weaknesses CWE-400
CWE-835
References
Metrics cvssV3_1

{'score': 4.9, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
GitHub_M
Published
Updated
Oct 29, 2026, 2:20 PM
Reserved
Oct 23, 2026, 1:28 PM
Status
Awaiting Analysis
Published
Oct 23, 2026, 9:17 PM
Modified
Oct 29, 2026, 3:17 PM
Severity
Moderate
Public date
Oct 23, 2026, 8:14 PM