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

Advisory record · `GHSA-2qrf-pqgx-qh9v`

- **Identifiers:** `GHSA-2qrf-pqgx-qh9v` · `CVE-2026-115774`
- **State:** Confirmed
- **Severity:** CVSS 4.9 Medium
- **Critical:** No
- **Weakness (CWE):** [CWE-400](https://cwe.mitre.org/data/definitions/400.html) · [CWE-835](https://cwe.mitre.org/data/definitions/835.html)
- **Tags:** [Denial of service](https://agentprime.io/advisories/tag/dos.md)
- **Published:** 23 Oct 2026
- **Updated:** 23 Oct 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 23 Oct 2026, 20:46 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `twisted` (PyPI): affected `<26.10.0rc1`; fixed in `26.10.0rc1`

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> Twisted versions before 26.10.0rc1 (the IMAP4 server in twisted.mail) are vulnerable to a denial of service. An authenticated IMAP client with a selected mailbox can send a SEARCH command with a negative literal size, which sends the parser into an infinite loop and freezes the single-threaded server process, stopping all other connections and co-hosted services until restart. Upgrade to Twisted 26.10.0rc1 or later; no workaround is listed.

Written 1 Nov 2026.

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 4.9 Medium, CVSS 3.1: `CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:N/A:H`, from CNA (GitHub_M)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0052, the 44th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 14:08 UTC: First seen by agentprime
- 31 Oct 2026, 14:08 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-2qrf-pqgx-qh9v)

## Sources

- [GitHub Advisory Database: GHSA-2qrf-pqgx-qh9v](https://github.com/advisories/GHSA-2qrf-pqgx-qh9v)
- [OSV: GHSA-2qrf-pqgx-qh9v](https://osv.dev/vulnerability/GHSA-2qrf-pqgx-qh9v)
- <https://github.com/twisted/twisted/security/advisories/GHSA-2qrf-pqgx-qh9v>
- <https://github.com/twisted/twisted/pull/12764>
- <https://github.com/twisted/twisted/commit/3d125548bcbe955007cb97f480bb699a5e074741>
- <https://github.com/twisted/twisted>
- <https://github.com/twisted/twisted/releases/tag/twisted-26.10.0rc1>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-2qrf-pqgx-qh9v>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-2qrf-pqgx-qh9v/>. Everything for agents: <https://agentprime.io/llms.txt>.