How severe is CVE-2025-64501?

CVE-2025-64501 has a CVSS score of 7.6/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2025-64501?

CVE-2025-64501 affects the following packages: prosemirror_to_html (RubyGems). Ecosystems affected: RubyGems.

How do I fix CVE-2025-64501?

Update prosemirror_to_html to 0.2.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-64501 is resolved across your whole dependency graph.

How do I detect CVE-2025-64501 in my RubyGems dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for prosemirror_to_html. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate CVE-2025-64501 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against CVE-2025-64501?

O3 pinpoints whether CVE-2025-64501 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is CVE-2025-64501 actively exploited in the wild?

No public exploit code has been indexed for CVE-2025-64501 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-2025-64501?

CVE-2025-64501 has an EPSS (Exploit Prediction Scoring System) score of 0.2%, placing it in the 8th 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.

When was CVE-2025-64501 published, and has it been updated?

CVE-2025-64501 was published on November 10, 2025 and was last updated on April 2, 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

CVE-2025-64501

HIGH

ProsemirrorToHtml: Cross-Site Scripting vulnerability through unescaped HTML attribute values

Also known asGHSA-52c5-vh7f-26fx

Published

Nov 10, 2025

Updated

Apr 2, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

EPSS Exploitation Probability

via FIRST.org ↗

0.2%probability of exploitation in next 30 days

Lower Risk8th percentile+0.16%

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

Blast Radius

1 pkg affected

💎prosemirror_to_html

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

ProsemirrorToHtml is a JSON converter which takes ProseMirror-compatible JSON and outputs HTML. In versions 0.2.0 and below, the prosemirror_to_html gem is vulnerable to Cross-Site Scripting (XSS) attacks through malicious HTML attribute values. While tag content is properly escaped, attribute values are not, allowing attackers to inject arbitrary JavaScript code. Applications that use prosemirror_to_html to convert ProseMirror documents to HTML, user-generated ProseMirror content, and end users viewing the rendered HTML output are all at risk of attack. This issue is fixed in version 0.2.1.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
💎RubyGems	`prosemirror_to_html`	all versions	0.2.1

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for prosemirror_to_html. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update prosemirror_to_html to 0.2.1 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-64501 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2025-64501 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2025-64501. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

ProsemirrorToHtml is a JSON converter which takes ProseMirror-compatible JSON and outputs HTML. In versions 0.2.0 and below, the `prosemirror_to_html` gem is vulnerable to Cross-Site Scripting (XSS) attacks through malicious HTML attribute values. While tag content is properly escaped, attribute values are not, allowing attackers to inject arbitrary JavaScript code. Applications that use `prosemirror_to_html` to convert ProseMirror documents to HTML, user-generated ProseMirror content, and end users viewing the rendered HTML output are all at risk of attack. This issue is fixed in version 0.2.

O3 Security · Impact-Aware SCA

Is CVE-2025-64501 in your dependencies?

O3 detects CVE-2025-64501 across RubyGems dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works