How severe is CVE-2026-47344?

No CVSS score has been assigned to CVE-2026-47344 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-47344?

CVE-2026-47344 affects the following packages: typo3/html-sanitizer (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2026-47344?

Update typo3/html-sanitizer to 2.3.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-47344 is resolved across your whole dependency graph.

How do I detect CVE-2026-47344 in my Packagist dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for typo3/html-sanitizer, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2026-47344 if there is no patch (or I can't update yet)?

Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Is CVE-2026-47344 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-47344 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2026-47344?

CVE-2026-47344 has an EPSS (Exploit Prediction Scoring System) score of 0.4%, placing it in the 37th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2026-47344?

CVE-2026-47344 is classified as Cross-site Scripting (XSS) (CWE-79), CWE-436 (CWE-436). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2026-47344 published, and has it been updated?

CVE-2026-47344 was published on June 8, 2026 and was last updated on October 21, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐘 Packagist

Not in CISA KEV

CVE-2026-47344 — html-sanitizer

Fix: TYPO3/html-sanitizer@bd1a88d

CVE-2026-47344 is a Cross-site Scripting (XSS) vulnerability in typo3/html-sanitizer. A fix is available for typo3/html-sanitizer — see the affected versions and patch details below.

TYPO3 HTML Sanitizer allows Cross-Site Scripting

Also known asGHSA-jvf5-rxvv-3mcg

Published

Jun 8, 2026

Updated

Oct 21, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Oct 22, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

Exploitation Status

No confirmed exploitation observed yet

CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-47344.

EPSS Exploitation Probability

via FIRST.org ↗

0.4%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs37th percentile — riskier than 37% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

Real-World Exposure

1 pkg affected

🐘typo3/html-sanitizer

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.

Description

When ALLOW_INSECURE_RAW_TEXT is enabled, whitespace-variant closing tags (e.g., </style\\t>) are not recognized by the sanitizer but accepted by browsers as valid end tags, allowing subsequent content to escape sanitization. This allows bypassing the cross-site scripting prevention mechanism of typo3/html-sanitizer before version 2.3.2.

Credits to IPC Labs for reporting this vulnerability.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`typo3/html-sanitizer`	all versions	2.3.2`composer require typo3/html-sanitizer:^2.3.2`

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for typo3/html-sanitizer, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update typo3/html-sanitizer to 2.3.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-47344 is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Frequently Asked Questions

When `ALLOW_INSECURE_RAW_TEXT` is enabled, whitespace-variant closing tags (e.g., `</style\\t>`) are not recognized by the sanitizer but accepted by browsers as valid end tags, allowing subsequent content to escape sanitization. This allows bypassing the cross-site scripting prevention mechanism of `typo3/html-sanitizer` before version 2.3.2. Credits to IPC Labs for reporting this vulnerability.

O3 Security · Impact-Aware SCA

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