---
title: "CVE-2026-44990: Apostrophe has default XSS via `xmp` raw-text passthrough in `sanitize-html`"
url: https://erroneo.us/security/cve/CVE-2026-44990/
description: "CVE-2026-44990 (sanitize-html (npm)): ApostropheCMS is an open-source Node.js content management system, and sanitize-html provides a simple HTML sanitizer…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-06-12
date_modified: 2026-09-10
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-44990"
kev: false
cvss: 9.3
epss: 0.00695
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-44990: Apostrophe has default XSS via `xmp` raw-text passthrough in `sanitize-html`

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Not in CISA KEV , but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 0.7% , percentile 52: FIRST’s model estimates a 0.7% chance of exploitation activity in the next 30 days, higher than 52% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Needs a user to click or open something. Phishing makes that realistic, but it is not wormable.
- Only applies if your dependency tree includes sanitize-html (npm) = 2.17.3, fixed in 2.17.4 . Check your lockfile, including transitive dependencies.

## What it is

ApostropheCMS is an open-source Node.js content management system, and sanitize-html provides a simple HTML sanitizer with a clear API. Under the default configuration, versions of sanitize-html prior to 2.17.4 can turn attacker-controlled content inside a disallowed xmp element into live HTML or JavaScript. This is a sanitizer bypass in the default disallowedTagsMode: 'discard' path and can lead to stored XSS in applications that render sanitized output back to users. Version 2.17.4 patches the issue.

## Affected packages

- npm `sanitize-html` = 2.17.3 → fixed: 2.17.4

## Affected products (CVE record)

- apostrophecms sanitize-html: < 2.17.4

## Severity

- GitHub_M CVSS 3.1: 9.3 `CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N`
- redhat-SADP CVSS 3.1: 8.1 `CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:N`
- GitHub CVSS 3.1: 9.3 `CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:N`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc , automatable no , technical impact total .
- FIRST EPSS (model of 2026-10-21): 0.69% probability of exploitation activity in the next 30 days; percentile 52.

## Sources

- [access.redhat.com](https://access.redhat.com/errata/RHSA-2026:41064)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2026:47737)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2026:36882)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2026:46903)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2026:57191)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2026:60386)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2026:46685)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2026:46598)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2026:63103)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2026:63046)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2026:60441)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2026:48124)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2026:41031)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2026:42146)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2026:43052)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2026:42796)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2026:41066)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2026:40262)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2026:51349)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2026:51196)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2026:51197)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2026:57194)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2026:59593)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2026:46885)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2026:41055)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2026:47735)
- [access.redhat.com](https://access.redhat.com/errata/RHSA-2026:36883)
- [GitHub Advisory GHSA-rpr9-rxv7-x643](https://github.com/advisories/GHSA-rpr9-rxv7-x643)
- [CVE.org record CVE-2026-44990](https://www.cve.org/CVERecord?id=CVE-2026-44990)
- [NVD entry CVE-2026-44990](https://nvd.nist.gov/vuln/detail/CVE-2026-44990)
- [github.com](https://github.com/apostrophecms/apostrophe/security/advisories/GHSA-rpr9-rxv7-x643)
- [access.redhat.com](https://access.redhat.com/security/cve/CVE-2026-44990)
- [RHBZ#2488565](https://bugzilla.redhat.com/show_bug.cgi?id=2488565)
- [security.access.redhat.com](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-44990.json)
- [github.com](https://github.com/apostrophecms/apostrophe/issues/5418)
- [github.com](https://github.com/apostrophecms/apostrophe/commit/8d4c882b4ed3a7ce802cd87f89f0c1cb7482b8c2)

---
Source page: https://erroneo.us/security/cve/CVE-2026-44990/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt