How severe is CVE-2018-6591?

CVE-2018-6591 has a CVSS score of 5.3/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2018-6591?

CVE-2018-6591 affects the following packages: converse.js (npm), jcbrand/converse.js (Packagist). Ecosystems affected: npm, Packagist.

How do I fix CVE-2018-6591?

Update converse.js to 3.3.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2018-6591 is resolved across your whole dependency graph.

How do I detect CVE-2018-6591 in my npm, Packagist dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for converse.js. 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-2018-6591 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-2018-6591?

O3 pinpoints whether CVE-2018-6591 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-2018-6591 actively exploited in the wild?

No public exploit code has been indexed for CVE-2018-6591 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-2018-6591?

CVE-2018-6591 has an EPSS (Exploit Prediction Scoring System) score of 1.1%, placing it in the 62th 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-2018-6591 published, and has it been updated?

CVE-2018-6591 was published on February 19, 2018 and was last updated on April 10, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

CVE-2018-6591: Converse.js Exposure of Sensitive Information (M…

EPSS Exploitation Probability

via FIRST.org ↗

1.1%probability of exploitation in next 30 days

Lower Risk62th percentile+0.86%

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

2 pkgs affected

📦converse.js🐘jcbrand/converse.js

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

Description

Converse.js and Inverse.js through 3.3 allow remote attackers to obtain sensitive information because it is too difficult to determine whether safe publication of private data was configured or even intended. For example, users might have an expectation that chatroom bookmarks are private, but the various interacting software components do not necessarily make that happen.

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`converse.js`	all versions	3.3.3
🐘Packagist	`jcbrand/converse.js`	all versions	3.3.3

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for converse.js. 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 converse.js to 3.3.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2018-6591 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-2018-6591 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-2018-6591. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

Converse.js and Inverse.js through 3.3 allow remote attackers to obtain sensitive information because it is too difficult to determine whether safe publication of private data was configured or even intended. For example, users might have an expectation that chatroom bookmarks are private, but the various interacting software components do not necessarily make that happen.

O3 Security · Impact-Aware SCA

Is CVE-2018-6591 in your dependencies?

O3 detects CVE-2018-6591 across npm, Packagist 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

CVE-2018-6591