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Medium 4.9Published Oct 23, 2026

CVE-2026-115774Twisted: Denial of Service in the Twisted IMAP4 Server via a Negative Literal Size in SEARCH

Updated under an hour ago ()

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It affects twisted. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

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.

CVSS
4.9 MEDIUM (v3.1, CNA)CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE)
CWE-400, CWE-835
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
GitHub_M
NVD analysis
Awaiting Analysis
Record last updated
Oct 23, 2026
First seen by InfoSec Signals
Oct 23, 2026

Affected products

Affected products
twisted twisted
twisted:twisted (from the name)
before 26.10.0rc1
CNA record

References

References

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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