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No exploitation reportedFix available

CVE-2020-15134

No exploitation reported by the sources we read.

  • Published2020-07-31
  • Fixed in1.4.0
  • WeaknessCWE-295

Am I affected?

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Description

Faye before version 1.4.0, there is a lack of certification validation in TLS handshakes. Faye uses em-http-request and faye-websocket in the Ruby version of its client. Those libraries both use the `EM::Connection#start_tls` method in EventMachine 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 was verified, but later WebSocket connections were not. This is fixed in Faye v1.4.0, which enables verification by default. For further background information on this issue, please see the referenced GitHub Advisory.

Timeline

dates in UTC
  1. 2020-07-3118:15CVE publishedNVD

Versions per branch

NVD · OSV
Faye project faye
BranchAffectedFixed in
1.4< 1.4.01.4.0

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Distribution builds and vendor advisories

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • ruby-fayeUbuntu:24.04:LTSall versions · no fixed version listed
  • ruby-fayeUbuntu:22.04:LTSall versions · no fixed version listed
  • ruby-fayeUbuntu:20.04:LTSall versions · no fixed version listed
  • ruby-fayeDebian:12all versions · fixed in 1.4.0-1

Full record on NVD

Fix

  1. Update Faye project faye to 1.4.0

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

  • CNACVSS 3.18known since 2026-10-23
  • NVDCVSS 3.18.7read 2026-10-23
  • NVDCVSS 2.06.4read 2026-10-23
  • CNAweakness (CWE)CWE-295known since 2026-10-23
  • NVDweakness (CWE)CWE-295read 2026-10-23
  • FIRST EPSSEPSS score0.9 %2026-11-08
  • OSVaffected packages—
  • GitHub AdvisoriesadvisoryHIGH2020-07-31

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N
Published
2020-07-31
Last Modified
2026-06-17
NVD status
Modified
GitHub Advisory
GHSA-3q49-h8f9-9fr9

Frequently asked questions

What is CVE-2020-15134?

Faye before version 1.4.0, there is a lack of certification validation in TLS handshakes. Faye uses em-http-request and faye-websocket in the Ruby version of its client. Those libraries both use the `EM::Connection#start_tls` method in EventMachine 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 was verified, but later WebSocket connections were not. This is fixed in Faye v1.4.0, which enables verification by default. For further background information on this issue, please see the referenced GitHub Advisory.

Is CVE-2020-15134 actively exploited?

Active exploitation of CVE-2020-15134 has not been confirmed. Its EPSS score was 0.9% on 2026-11-08, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2020-15134?

CVE-2020-15134 has a CVSS v3 base score of 8.7 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N.

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