GHSA-jj54-5q2m-q7pj CVE-2021-32026 GO-2024-2850
NATS server TLS missing ciphersuite settings when CLI flags used
- Severity
- Low
- The publisher's own rating, not a CVSS score
- Exploit chance (EPSS)
- —
- No score published
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- —
- Not classified
- Fix
2.2.3- Upgrade github.com/nats-io/nats-server/v2 to this version or later
Description
(This advisory is canonically https://advisories.nats.io/CVE/CVE-2021-32026.txt)
Problem Description
The NATS server by default uses a restricted set of modern ciphersuites for TLS. This selection can be overridden through configuration. The defaults include just RSA and ECDSA with either AES/GCM with a SHA2 digest or ChaCha20/Poly1305.
The configuration system allows for extensive use of CLI options to override configuration settings. When using these to set a key/cert for TLS, the restricted ciphersuite settings were lost, enabling all ciphersuites supported by Go by default.
None of these additional ciphersuites are broken, so the NATS maintainers have fixed this in public git and the next release is not being hurried, nor is this security advisory embargoed.
Affected versions
NATS Server:
- All versions prior to 2.2.3
- fixed with nats-io/nats-server commit ffccc2e1bd (2021-04-29)
Impact
If a server administrator chooses to start the nats-server with TLS configuration parameters provided on the command-line, then clients can negotiate TLS ciphersuites which were not expected.
Workaround
Use a configuration file to set the TLS parameters instead of command-line options.
Solution
Upgrade the NATS server.
Credits
This issue was identified and reported by SimCorp.
Affected versions
Go
| Package | Vulnerable | Fixed in |
|---|---|---|
| github.com/nats-io/nats-server | all versions |
No fix yet |
| github.com/nats-io/nats-server/v2 | < 2.2.3 |
2.2.3 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
github.com/nats-io/nats-server/v2 Go → 2.2.3
- go
go get github.com/nats-io/nats-server/v2@v2.2.3 && go mod tidy
References
Packages
Other links
Timeline
- Published
- Last updated by the source
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-pq2q-rcw4-3hr6 NATS: Pre-auth remote server crash via WebSocket frame length overflow in wsRead | High | Also affects github.com/nats-io/nats-server |
| GHSA-3f24-pcvm-5jqc NATS has mTLS verify_and_map authentication bypass via incorrect Subject DN matching | Medium | Also affects github.com/nats-io/nats-server |
| GHSA-55h8-8g96-x4hj NATS: Leafnode connections allow spoofing of Nats-Request-Info identity headers | Medium | Also affects github.com/nats-io/nats-server |
| GHSA-pwx7-fx9r-hr4h NATS Server: Incomplete Stripping of Nats-Request-Info Header Allows Identity Spoofing | Medium | Also affects github.com/nats-io/nats-server |
| GHSA-9983-vrx2-fg9c NATS JetStream has an authorization bypass through its Management API | Medium | Also affects github.com/nats-io/nats-server |
| GHSA-8r68-gvr4-jh7j NATS is vulnerable to pre-auth DoS through WebSockets client service | Medium | Also affects github.com/nats-io/nats-server |
| GHSA-vprv-35vv-q339 NATS has pre-auth server panic via leafnode handling | High | Also affects github.com/nats-io/nats-server |
| GHSA-jxxm-27vp-c3m5 NATS allows MQTT clients to bypass ACL checks | Medium | Also affects github.com/nats-io/nats-server |
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