---
id: "CVE-2026-121603"
kind: "vulnerability"
aliases: ["CVE-2026-121603"]
title: "Solanum IRC server: overlong kill reason overflows buffer, risks code execution"
severity: "high"
cvss: 8.5
epss: null
exploited: false
status: "open"
category: "runtime"
products: []
ecosystems: []
tags: ["irc", "runtime", "self-hosted", "solanum"]
not_affected_if: ["newer-commit", "no-server-links", "trusted-peers-only"]
published_at: "2026-11-03T17:18:11+00:00"
first_seen_at: "2026-11-03T17:21:56+00:00"
updated_at: "2026-11-03T17:23:56+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-121603", "first_seen_at": "2026-11-03T17:21:56+00:00"}]
---

# Solanum IRC server: overlong kill reason overflows buffer, risks code execution

Solanum, an IRC server daemon, has a buffer overflow in its ms_kill() handler: a linked server sending a kill reason longer than KILLLEN overflows a static 512-byte buffer. The result is a crash of the ircd, and possibly remote code execution.

_Summary, check and fix written by a model from the sources; labelled as such._

## How to check

- Check the installed Solanum version or git commit and compare it with commit `2ea1382`; builds before that commit are exposed.
- Check whether the server accepts server-to-server links from peers you do not fully control.

## Fix

- Solanum: move to a build that includes commit `2ea1382` or later (the patch linked from the sources).

## Timeline

- 2026-11-03T17:21:56+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-121603

## Documents

- [advisory] Third-party advisory: www.vulncheck.com https://www.vulncheck.com/advisories/solanum-before-commit-2ea1382-buffer-overflow-via-server-to-server-kill-handler
- [fix] Patch: github.com https://github.com/solanum-ircd/solanum/commit/2ea1382e4262b212a91034258c466f0f6754cd61

## From the sources

Solanum before commit 2ea1382 contains a buffer overflow vulnerability in ms_kill() that allows malicious linked servers to corrupt memory by sending an overlong kill reason. Attackers controlling a rogue or compromised peer server can send a reason exceeding KILLLEN that overflows a static 512-byte buffer, crashing the ircd or potentially achieving remote code execution.

---

_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_