CVE-2020-15133 json
Missing TLS certificate verification in Faye Websocket
published 6y ago modified last mo. also GHSA-2v5c-755p-p4gv , EUVD-2020-0529
- cvss
- 8.0
- version 3.1, CNA
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.9%
- EPSS 0.9% chance of exploitation in 30 days, percentile 60%
- public exploits
- 0
- none known
Summary
In faye-websocket before version 0.11.0, there is a lack of certification validation in TLS handshakes. The `Faye::WebSocket::Client` class uses 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 `wss:` connection made using this library is vulnerable to a man-in-the-middle attack, since it does not confirm the identity of the server it is connected to. For further background information on this issue, please see the referenced GitHub Advisory. Upgrading `faye-websocket` to v0.11.0 is recommended.
Patch / fix
- rubygems faye-websocket 0.11.0
- faye-websocket_project faye-websocket 0.11.0
- ruby-faye-websocket Debian 14, Debian 13, Debian 12 0.11.0-1
debian advisories DEBIAN-CVE-2020-15133
- github.com/eventmachine/eventmachine#378 pull request
- github.com/faye/faye-websocket-ruby#129 pull request
- github.com/igrigorik/em-http-request#340 pull request
Is CVE-2020-15133 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.
Check with FencerExploit prediction
0.92% chance of exploitation in the next 30 days, higher than 60% of all scored CVEs (FIRST EPSS, 2026-11-09).
Exploits and checks
- blog.jcoglan.com https://blog.jcoglan.com/2020/07/31/missing-tls-verification-in-faye/ referenced PoC, tagged "exploit" by a source, unverified
- github.com https://github.com/faye/faye-websocket-ruby/security/advisories/GHSA-2v5c-755p-p4gv referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 3.1 | 8.0 | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N |
| NVD | 3.1 | 8.7 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:N |
| NVD | 2.0 | 5.8 | AV:N/AC:M/Au:N/C:P/I:P/A:N |
| GitHub | 3.1 | 8.0 | CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:C/C:H/I:H/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| rubygems | faye-websocket | <0.11.0 |
0.11.0 |
Affected products
- faye faye-websocket
Classification
- Weakness
-
- CWE-295 Improper Certificate Validation
References
-
github.com
/eventmachine/eventmachine/pull/378
web
-
github.com
/faye/faye-websocket-ruby/pull/129
web
-
github.com
/igrigorik/em-http-request/pull/340
web
-
blog.jcoglan.com
/2020/07/31/missing-tls-verification-in-faye/
exploit, third-party-advisory
-
github.com
/faye/faye-websocket-ruby/security/advisories/GHSA-2v5c-755p-p4gv
web, exploit, third-party-advisory
-
nvd.nist.gov
/vuln/detail/CVE-2020-15133
advisory
-
github.com
/eventmachine/eventmachine/issues/275
web
-
github.com
/eventmachine/eventmachine/issues/814
web
-
github.com
/faye/faye/issues/524
web
-
blog.jcoglan.com
/2020/07/31/missing-tls-verification-in-faye
web
-
github.com
/faye/faye-websocket-ruby
package
-
github.com
/rubysec/ruby-advisory-db/blob/master/gems/faye-websocket/CVE-2020-15133.yml
web
-
securitylab.github.com
/advisories/GHSL-2020-094-igrigorik-em-http-request
advisory
-
rubydoc.info
/github/eventmachine/eventmachine/EventMachine/Connection:ssl_verify_peer
web
-
rubydoc.info
/github/eventmachine/eventmachine/EventMachine/Connection:start_tls
web
Sources
- CVE List CVE-2020-15133
- GitHub Advisory GHSA-2v5c-755p-p4gv
- NVD CVE-2020-15133
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