Open-Source Security Intelligence

Know every vulnerability
before it knows you.

DevGuard continuously monitors your dependencies and alerts you when CVEs like this one affect your stack — with real-time threat intelligence built for developers.

Checkout DevGuardView on GitHub
Search

GHSA-3g76-f9xq-8vp6

MediumCVSS 5.3 / 10
Published May 9, 2026·Last modified Jun 2, 2026
Affected Components(0)

No affected components available

Description

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. Send repeated connections with distinct matching SNI values.
  4. Observe that the SNI cache size grows with the number of unique matching names.

What are the affected versions?

Affected released versions confirmed on origin:

  • 4.3.4 through 4.3.8
  • 4.4.0 through 4.4.9
  • 4.5.0 through 4.5.26
  • 5.0.0 through 5.0.11

Not affected by the same sink:

  • 4.0.x through 4.2.x
  • 4.3.0 through 4.3.3
Risk Scores
Base Score
5.3

The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a low impact on the availability of the system.

Threat Intelligence
4.9

Exploitation attempts have been detected. Elevated vigilance and prompt remediation are advised.

EPSS
0.24%

The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

Related Vulnerabilities

Browse More

Medium severity
Scan your project

Continuously monitor your dependencies and get alerted when vulnerabilities like this one affect your stack.

Checkout DevGuard