CVE-2026-115774

4.9 MEDIUM 0.5% exploit odds Fix listed Denial of service Library

What it is

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.

At a glance

Exploitability: Can be exploited over the network with an admin-level account. High risk of service disruption.
Exploit odds: 0.5% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2026-10-23 21:17 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-10-29 15:17 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.5% in the next 30 days (EPSS).
Severity: 4.9 MEDIUM (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2026-10-23 21:17 UTC
Last modified: 2026-10-29 15:17 UTC
Exploit probability: 0.5% · EPSS, next 30 days
Weakness: CWE-400 · Uncontrolled resource consumption
Record status: Awaiting Analysis

Attack profile CVSS 3.1 · 4.9

Attack vector: Network
Complexity: Low
Privileges needed: High
User interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

Raw vector

CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H

Is it in your code?

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Read https://cve-list.com/agent/cve/CVE-2026-115774.md and follow it. Check whether this project is affected by CVE-2026-115774. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record