Missing TLS certificate verification

Exploitation

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

CVSS

8.0 · CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N

EPSS

• CVE-2020-15134: 0.86% estimated exploitation activity in the next 30 days; percentile 58.67 (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.

Faye uses [em-http-request][6] and [faye-websocket][10] in the Ruby version of its client. Those libraries both use the [EM::Connection#starttls][1] method in [EventMachine][2] to implement the TLS handshake whenever a wss: URL is used for the connection. This method does not implement certificate verification by default, meaning that it does not check that the server presents a valid and trusted TLS certificate for the expected hostname. That means that any https: or wss: connection made using these libraries is vulnerable to a man-in-the-middle attack, since it does not confirm the identity of the server it is connected to. The first request a Faye client makes is always sent via normal HTTP, but later messages may be sent via WebSocket. Therefore it is vulnerable to the same problem that these underlying libraries are, and we needed both libraries to support TLS verification before Faye could claim to do the same. Your client would still be insecure if its initial HTTPS request…

Published by the source

31 Jul 2020, 17:39 UTC

Last modified by the source

25 May 2023, 05:00 UTC

Source last checked

26 Oct 2026, 15:47 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-3q49-h8f9-9fr9

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# Patch Next advisory brief: CVE-2020-15134

Advisory: Missing TLS certificate verification
IDs: CVE-2020-15134, GHSA-3q49-h8f9-9fr9
Record: https://patchnext.com/advisories/cve-2020-15134 (revision 1, source checked 26 Oct 2026, 15:47 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.0)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: faye 1.4.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- RubyGems faye: affected < 1.4.0; fixed in 1.4.0

## Suggested inspection (read-only)
- RubyGems faye: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on faye.
- 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-3q49-h8f9-9fr9 (GitHub-reviewed advisory GHSA-3q49-h8f9-9fr9 lists affected ranges: RubyGems faye >=0 <1.4.0)

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