How severe is CVE-2023-23627?

CVE-2023-23627 has a CVSS score of 6.1/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2023-23627?

CVE-2023-23627 affects the following packages: sanitize (RubyGems). Ecosystems affected: RubyGems.

How do I fix CVE-2023-23627?

Update sanitize to 6.0.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-23627 is resolved across your whole dependency graph.

How do I detect CVE-2023-23627 in my RubyGems dependencies?

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

How do I mitigate CVE-2023-23627 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-2023-23627 actively exploited in the wild?

No public exploit code has been indexed for CVE-2023-23627 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-2023-23627?

CVE-2023-23627 has an EPSS (Exploit Prediction Scoring System) score of 0.5%, placing it in the 45th 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-2023-23627?

CVE-2023-23627 is classified as Cross-site Scripting (XSS) (CWE-79). This weakness type 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-2023-23627 published, and has it been updated?

CVE-2023-23627 was published on January 27, 2023 and was last updated on October 28, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

💎

💎 RubyGems

Not in CISA KEV

MEDIUM severity

CVE-2023-23627 — sanitize

MEDIUMFix: rgrove/sanitize@ec14265

CVE-2023-23627 is a medium-severity (CVSS 6.1) Cross-site Scripting (XSS) vulnerability in sanitize. A fix is available for sanitize — see the affected versions and patch details below.

Sanitize vulnerable to Cross-site Scripting via Improper neutralization of `noscript` element

Also known asGHSA-fw3g-2h3j-qmm7

Published

Jan 27, 2023

Updated

Oct 28, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Nov 4, 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-2023-23627.

EPSS Exploitation Probability

via FIRST.org ↗

0.5%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs45th percentile — riskier than 45% of all scored CVEsHighest risk

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

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected

💎sanitize

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

Description

Impact

Using carefully crafted input, an attacker may be able to sneak arbitrary HTML through Sanitize >= 5.0.0, < 6.0.1 when Sanitize is configured with a custom allowlist that allows noscript elements. This could result in XSS (cross-site scripting) or other undesired behavior when that HTML is rendered in a browser.

Sanitize's default configs don't allow noscript elements and are not vulnerable. This issue only affects users who are using a custom config that adds noscript to the element allowlist.

Patches

Sanitize >= 6.0.1 always removes noscript elements and their contents, even when noscript is in the allowlist.

Workarounds

Users who are unable to upgrade can prevent this issue by using one of Sanitize's default configs or by ensuring that their custom config does not include noscript in the element allowlist.

Details

The root cause of this issue is that HTML parsing rules treat the contents of a noscript element differently depending on whether scripting is enabled in the user agent. Nokogiri (the HTML parser Sanitize uses) doesn't support scripting so it follows the "scripting disabled" rules, but a web browser with scripting enabled will follow the "scripting enabled" rules. This means that Sanitize can't reliably make the contents of a noscript element safe for scripting enabled browsers. The safest thing to do is to remove the element and its contents entirely, which is now what Sanitize does in version 6.0.1 and later.

References

Release Notes

Credit

Thanks to David Klein from TU Braunschweig (@leeN) for reporting this issue.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
💎RubyGems	`sanitize`	≥ 5.0.0&&< 6.0.1	6.0.1`bundle update sanitize --conservative`

Affected Products

1 product · 1 configurations

Application

sanitizesanitize_project

≥ 5.0.0 && < 6.0.1

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for sanitize, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update sanitize to 6.0.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2023-23627 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

### Impact Using carefully crafted input, an attacker may be able to sneak arbitrary HTML through Sanitize `>= 5.0.0, < 6.0.1` when Sanitize is configured with a custom allowlist that allows `noscript` elements. This could result in XSS (cross-site scripting) or other undesired behavior when that HTML is rendered in a browser. Sanitize's default configs don't allow `noscript` elements and are not vulnerable. This issue only affects users who are using a custom config that adds `noscript` to the element allowlist. ### Patches Sanitize `>= 6.0.1` always removes `noscript` elements and their