CVE-2026-115774 Twisted: Denial of Service in the Twisted IMAP4 Server via a Negative Literal Size in SEARCH
- Exploited in the wild
- Not known
- Fix
- Available
What is CVE-2026-115774?
CVE-2026-115774 is a medium-severity vulnerability in twisted, published on 23 Oct 2026.
Official 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.
Which versions are affected by CVE-2026-115774?
2 open source packages ship an affected version, including Twisted and twisted.
| Package | Affected | Fixed in |
|---|---|---|
Twisted PyPI | All versions | 26.10.0rc1 |
twisted PyPI | All versions | 26.10.0rc1 |
How do I fix CVE-2026-115774?
Upgrade Twisted to 26.10.0rc1 or later.
Is CVE-2026-115774 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-115774 exists.
Sources
Also known as AZL-111416, DEBIAN-CVE-2026-115774, ECHO-f150-d773-3934, GHSA-2qrf-pqgx-qh9v, UBUNTU-CVE-2026-115774.