---
id: "CVE-2026-114723"
kind: "vulnerability"
aliases: ["CVE-2026-114723"]
title: "Roundcube Webmail: image thumbnail fallback skips memory limit, exhausting server memory"
severity: "low"
cvss: 3.7
epss: 0.00332
exploited: false
status: "open"
category: "package"
products: []
ecosystems: []
tags: ["mail", "package", "php", "roundcube", "self-hosted"]
not_affected_if: ["managed-hosting", "windows"]
published_at: "2026-10-22T02:17:00+00:00"
first_seen_at: "2026-10-23T21:57:30+00:00"
updated_at: "2026-10-25T04:43:29+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-114723", "first_seen_at": "2026-10-23T21:57:30+00:00"}, {"source": "epss", "url": "https://api.first.org/data/v1/epss?cve=CVE-2026-114723", "first_seen_at": "2026-10-24T07:15:52+00:00"}]
---

# Roundcube Webmail: image thumbnail fallback skips memory limit, exhausting server memory

Roundcube Webmail's thumbnail code falls back to GD when ImageMagick is unavailable, and the memory check only ran on Windows. A crafted image with large dimensions can therefore make the server exhaust its memory.

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

## How to check

- Check the installed Roundcube version with `grep -i 'RCMAIL_VERSION' program/include/iniset.php` or the version shown in the Roundcube admin About page.
- Check whether the PHP GD extension is loaded with `php -m | grep -i gd`.

## Fix

- Upgrade Roundcube Webmail to `1.6.20` on the 1.6 branch or `1.7.5` on the 1.7 branch.
- Until upgraded, unknown whether disabling thumbnail generation or setting a PHP `memory_limit` is a sufficient workaround.

## Timeline

- 2026-10-23T21:57:30+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-114723
- 2026-10-24T07:15:52+00:00 epss https://api.first.org/data/v1/epss?cve=CVE-2026-114723

## From the sources

Roundcube Webmail before 1.6.20 and 1.7.x before 1.7.5 allows the ImageMagick resource limits to be bypassed during thumbnail generation. When rcube_image falls back to GD, the available-memory check was applied only on Windows, so on other platforms a crafted image with large dimensions was processed by GD without any resource limit and could exhaust server memory. Upstream fixed this in the commit “Fix ImageMagick resource limits bypass by GD fallback during thumbnail generation”, which applies the memory check on all platforms.

---

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