CVE-2026-40186: ApostropheCMS is an open-source Node.js content management system

Routine

MEDIUM 6.1DOWNGRADEUPGRADE

CVE-2026-40186 is a medium-severity flaw (CVSS 6.1) affecting apostrophecms, sanitize-html. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

ApostropheCMS is an open-source Node.js content management system. A regression introduced in commit 49d0bb7, included in versions 2.17.1 of the ApostropheCMS-maintained sanitize-html package bypasses allowedTags enforcement for text inside nonTextTagsArray elements (textarea and option). ApostropheCMS version 4.28.0 is affected through its dependency on the vulnerable sanitize-html version. The code at packages/sanitize-html/index.js:569-573 inc

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	6.1 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.2% (top 84%)
CISA exploited list	No
Weakness	CWE-79
Published	2026-04-15
Last modified	2026-10-26

Publisher (CNA): GitHub, Inc. · Vendor: apostrophecms

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-15 21:17 UTCPublished CVE record published
2026-10-26 21:10 UTCUpdated Record last modified

apostrophecms apostrophecms DOWNGRADE

Affected: 4.29.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 4.29.0

1. Check installed version

apt-cache policy apostrophecms || rpm -q apostrophecms || apostrophecms --version

2. No fixed release: DOWNGRADE to a release before 4.29.0 (Debian / Ubuntu)

apt-cache madison apostrophecms sudo apt install apostrophecms=<VERSION_BEFORE_4.29.0> sudo apt-mark hold apostrophecms

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list apostrophecms sudo dnf downgrade apostrophecms-<VERSION_BEFORE_4.29.0> sudo dnf versionlock add apostrophecms

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

apostrophecms sanitize-html UPGRADE

Affected: <= 2.17.1

Fixed in: newer than 2.17.1

Safe to downgrade to: no unaffected older release

1. Check installed version

npm ls sanitize-html

2. UPGRADE to newer than 2.17.1

npm install sanitize-html@">2.17.1"

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-40186?

apostrophecms: downgrade or apply the listed mitigation; sanitize-html: upgrade to newer than 2.17.1. Exact commands for each OS are on this page.

Is CVE-2026-40186 being exploited?

CVE-2026-40186 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-40186 affect?

CVE-2026-40186 affects apostrophecms, sanitize-html. Severity is medium (CVSS 6.1). ApostropheCMS is an open-source Node.js content management system. A regression introduced in commit 49d0bb7, included in versions 2.17.1 of the ApostropheCMS-maintained sanitize-html package bypasses allowedTags enforcement for text inside

How urgent is CVE-2026-40186?

Priority 30/100. Public exploit reference

Software pages

Node.js vulnerabilities

Related CVEs

CVE-2026-35569 HIGH 8.7 UPGRADE ApostropheCMS is an open-source Node.js content management system
CVE-2026-39857 MEDIUM 5.3 UPGRADE ApostropheCMS is an open-source Node.js content management system
CVE-2026-33877 LOW 3.7 UPGRADE ApostropheCMS is an open-source Node.js content management system
CVE-2026-33889 MEDIUM 5.4 UPGRADE ApostropheCMS is an open-source Node.js content management system
CVE-2026-33888 MEDIUM 5.3 UPGRADE ApostropheCMS is an open-source Node.js content management system

References

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