An issue was discovered in the /api/connector endpoint handler in Yubico…
Priority LOW 36CWE-835Published · 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-835.
Summary
An issue was discovered in the /api/connector endpoint handler in Yubico yubihsm-connector before 3.0.1 (in YubiHSM SDK before 2021.04). The handler did not validate the length of the request, which can lead to a state where yubihsm-connector becomes stuck in a loop waiting for the YubiHSM to send it data, preventing any further operations until the yubihsm-connector is restarted. An attacker can send 0, 1, or 2 bytes to trigger this.
Why it matters now
EPSS 0.01521 74th percentileScored 2026-11-07
Fix Fixed github.com/Yubico/yubihsm-connector (Go): 3.0.1
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/Yubico/yubihsm-connector (Go) | before 3.0.1 | 3.0.1 | Patch available | GHSA-8m9g-647g-5pxw |
- — Vendor— Affected all versions Fixed in — No fix listed CNA
- github.com/Yubico/yubihsm-connector (Go) Vendor— Affected before 3.0.1 Fixed in 3.0.1 Patch available GHSA-8m9g-647g-5pxw
CPE configurations NVD · 2
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:yubico:yubihsm_connector:*:*:*:*:*:*:*:* | before 3.0.1 | Vulnerable | Yubico |
| cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:* | 34 | Vulnerable | Fedoraproject |
- cpe:2.3:a:yubico:yubihsm_connector:*:*:*:*:*:*:*:* Versions before 3.0.1 Vulnerable ·Yubico
- cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:* Versions 34 Vulnerable ·Fedoraproject
Remediation
- Fix · GHSA-8m9g-647g-5pxw github.com/Yubico/yubihsm-connector (Go) Fixed in 3.0.1 Advisory →
Vendor assessments
Timeline
- 2026-10-02 Threatist record created from CVE-2021-28484
- 2026-10-03 Alias added: GHSA-8m9g-647g-5pxw
References
Advisory 4
Sources
- CVE-2021-28484 · CVE Program
- CVE-2021-28484 · NVD
- FIRST EPSS
- GHSA-8m9g-647g-5pxw · GitHub Advisory Database · CC BY 4.0
- CVE-2021-28484 · 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