The JWT library in NATS nats-server before 2.1.9 allows a denial of service (a nil dereference in Go code).
Priority LOW 37CWE-476Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA and GitHub. Impact type from CWE-476.
Summary
The JWT library in NATS nats-server before 2.1.9 allows a denial of service (a nil dereference in Go code).
Why it matters now
EPSS 0.02157 82nd percentileScored 2026-11-07
Fix Fixed github.com/nats-io/jwt (Go): 1.1.0
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | — | all versions | — | No fix listed | CNA |
| — | github.com/nats-io/jwt (Go) | before 1.1.0 | 1.1.0 | Patch available | GHSA-h2fg-54x9-5qhq |
- — Vendor— Affected all versions Fixed in — No fix listed CNA
- github.com/nats-io/jwt (Go) Vendor— Affected before 1.1.0 Fixed in 1.1.0 Patch available GHSA-h2fg-54x9-5qhq
CPE configurations NVD · 2
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:linuxfoundation:nats-server:*:*:*:*:*:*:*:* | before 2.1.9 | Vulnerable | backstage |
| cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:* | 33 | Vulnerable | Fedoraproject |
- cpe:2.3:a:linuxfoundation:nats-server:*:*:*:*:*:*:*:* Versions before 2.1.9 Vulnerable ·backstage
- cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:* Versions 33 Vulnerable ·Fedoraproject
Remediation
- Fix · GHSA-h2fg-54x9-5qhq github.com/nats-io/jwt (Go) Fixed in 1.1.0 Advisory →
Vendor assessments
Timeline
- 2026-10-02 Threatist record created from CVE-2020-26521
- 2026-10-03 Alias added: GHSA-h2fg-54x9-5qhq
References
Advisory 3
Other 7
- https://github.com/nats-io/jwt/security/advisories/GHSA-h2fg-54x9-5qhq
- https://github.com/nats-io/jwt/pull/107
- https://github.com/nats-io/nats-server/commit/9ff8bcde2e46009e98bd9e88f598af355f62c168
- https://advisories.nats.io/CVE/CVE-2020-26521.txt
- https://github.com/nats-io/jwt
- https://lists.fedoraproject.org/archives/list/[email protected]/message/VT67XCLIIBYRT762SVFBYFFTQFVSM3SI
- https://pkg.go.dev/vuln/GO-2022-0402
Sources
- CVE-2020-26521 · CVE Program
- CVE-2020-26521 · NVD
- FIRST EPSS
- GHSA-h2fg-54x9-5qhq · GitHub Advisory Database · CC BY 4.0
- CVE-2020-26521 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences