CVE-2026-6860
CVE-2026-6860 is a CWE-770 vulnerability in io.vertx:vertx-core. O3 Security confirms whether CVE-2026-6860 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.
Vert.x has a DoS via unbounded server-side SNI SslContext cache growth
Blast Radius
io.vertx:vertx-core☕io.vertx:vertx-core☕io.vertx:vertx-core☕io.vertx:vertx-coreReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.
Description
A TCP client can perform a TLS handshake and present the server name extension with a server name that is accepted by a server wildcard name, e.g. if the server is configured with a certificate accepting *.example.com, any XYZ.example.com where xyz is a valid name can be used.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | io.vertx:vertx-core | ≥ 4.3.4 | No fix |
| ☕Maven | io.vertx:vertx-core | ≥ 4.4.0 | No fix |
| ☕Maven | io.vertx:vertx-core | ≥ 4.5.0&&< 4.5.27 | 4.5.27 |
| ☕Maven | io.vertx:vertx-core | ≥ 5.0.0&&< 5.0.12 | 5.0.12 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for io.vertx:vertx-core. 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
No patched version of io.vertx:vertx-core has shipped for CVE-2026-6860 yet. Where your build allows, override or pin the dependency away from the vulnerable range, and apply any maintainer-recommended mitigation.
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-2026-6860 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-2026-6860. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2026-6860 in your dependencies?
O3 detects CVE-2026-6860 across Maven dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.