---
title: "CVE-2023-43770: Roundcube Webmail Persistent Cross-Site Scripting (XSS) Vulnerability"
url: https://erroneo.us/security/cve/CVE-2023-43770/
description: "CVE-2023-43770 (Roundcube Webmail): Exploited in the wild (CISA KEV). Roundcube before 1.4.14, 1.5.x before 1.5.4, and 1.6.x before 1.6.3 allows XSS via…"
type: vulnerability-record
section: "Security Digest"
date_published: 2023-09-22
date_modified: 2025-10-21
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2023-43770"
kev: true
cvss: 6.1
epss: 0.6366
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2023-43770: Roundcube Webmail Persistent Cross-Site Scripting (XSS) Vulnerability

**Signal:** Exploited: patch now if you run it. CISA has confirmed exploitation in the wild. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Yes, if you run Roundcube Webmail. CISA added this CVE to its Known Exploited Vulnerabilities catalog on 2024-02-12, which means there is reliable evidence of exploitation in the wild. US federal agencies must remediate by 2024-03-04 ; treat that as the outer limit, not the target.
- EPSS 63.7% , percentile 99: FIRST’s model estimates a 63.7% chance of exploitation activity in the next 30 days, higher than 99% of all scored CVEs (very high). EPSS is a probability, not a verdict.
- Needs a user to click or open something. Phishing makes that realistic, but it is not wormable.

## What it is

Roundcube before 1.4.14, 1.5.x before 1.5.4, and 1.6.x before 1.6.3 allows XSS via text/plain e-mail messages with crafted links because of program/lib/Roundcube/rcubestringreplacer.php behavior.

## Affected products (CVE record)

- n/a n/a: see advisory

## Severity

- CISA-ADP CVSS 3.1: 6.1 `CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N`

## Exploitation

- CISA KEV: added 2024-02-12; federal due date 2024-03-04. Known ransomware use: Unknown.
- CISA required action: Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
- CISA SSVC assessment: exploitation active , automatable no , technical impact partial .
- FIRST EPSS (model of 2026-10-21): 63.66% probability of exploitation activity in the next 30 days; percentile 99.

## Sources

- [Listed in CISA KEV notes (roundcube.net)](https://roundcube.net/news/2023/09/15/security-update-1.6.3-released)
- [CVE.org record CVE-2023-43770](https://www.cve.org/CVERecord?id=CVE-2023-43770)
- [NVD entry CVE-2023-43770](https://nvd.nist.gov/vuln/detail/CVE-2023-43770)
- [CISA Known Exploited Vulnerabilities catalog entry](https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2023-43770)
- [github.com](https://github.com/roundcube/roundcubemail/commit/e92ec206a886461245e1672d8530cc93c618a49b)
- [[debian-lts-announce] 20230922 [SECURITY] [DLA 3577-1] roundcube security update](https://lists.debian.org/debian-lts-announce/2023/09/msg00024.html)

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Source page: https://erroneo.us/security/cve/CVE-2023-43770/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt