Vert.x has a DoS via unbounded server-side SNI SslContext cache growth

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

6.9 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:L · score source

EPSS

• CVE-2026-6860: 0.24% estimated exploitation activity in the next 30 days; percentile 14.87 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Potential unbounded server-side SNI SslContext cache growth in Vert.x TLS handling, with = resource-exhaustion / DoS impact. On affected versions, matching server-side SNI names are cached via computeIfAbsent(serverName, ...) in a serverName-keyed SslContext cache. The implementation differs slightly by branch, but the same sink appears to be present in released versions 4.3.4 through 5.0.11: - 4.3.x: SSLHelper - 4.4.x / 4.5.x: SslChannelProvider - 5.0.x and current master: SslContextProvider When server-side SNI is enabled and wildcard or otherwise broad hostname mappings are used, an unauthenticated client can send many distinct matching SNI names and cause the server to retain increasing numbers of SslContext entries over time, leading to increasing memory consumption and possible DoS conditions. Steps to reproduce 1. Configure a Vert.x server with setSsl(true) and setSni(true). 2. Use a keystore or mapping where many distinct SNI names match a wildcard or similarly broad rule. 3.…

Published by the source

9 May 2026, 00:38 UTC

Last modified by the source

2 Jun 2026, 22:07 UTC

Source last checked

26 Oct 2026, 16:45 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-3g76-f9xq-8vp6

Preview the exact text before you copy it. Commands are read-only suggestions; review them before running anything.

# Patch Next advisory brief: CVE-2026-6860

Advisory: Vert.x has a DoS via unbounded server-side SNI SslContext cache growth
IDs: CVE-2026-6860, GHSA-3g76-f9xq-8vp6
Record: https://patchnext.com/advisories/cve-2026-6860 (revision 1, source checked 26 Oct 2026, 16:45 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.9)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Partial vendor fix; fixed versions by package: io.vertx:vertx-core 5.0.12, 4.5.27. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven io.vertx:vertx-core: affected >= 4.3.4, <= 4.3.8; >= 4.4.0, <= 4.4.9; >= 4.5.0, <= 4.5.26; >= 5.0.0, <= 5.0.11; fixed in 4.5.27, 5.0.12

## Suggested inspection (read-only)
- Maven io.vertx:vertx-core: check the installed version with your package manager.

## Supported action
No complete vendor fix is recorded. Follow the primary source's mitigation guidance and check this record again before closing anything.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on io.vertx:vertx-core.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-3g76-f9xq-8vp6 (GitHub-reviewed advisory GHSA-3g76-f9xq-8vp6 lists affected ranges: Maven io.vertx:vertx-core >=4.3.4 =4.4.0 =4.5.0 =5.0.0 <=5.0.11)

Commands are suggestions: review each one before running it.