CVE-2021-27565
The web server in InterNiche NicheStack through 4.0.1 allows remote attackers to cause a denial...
The web server in InterNiche NicheStack through 4.0.1 allows remote attackers to cause a denial of service (infinite loop and networking outage) via an unexpected valid HTTP request such as OPTIONS. This occurs because the HTTP request handler enters a miscoded wbs_loop() debugger hook.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- High
Exploit likelihood
What each source reports
NVD Score used
The web server in InterNiche NicheStack through 4.0.1 allows remote attackers to cause a denial of service (infinite loop and networking outage) via an unexpected valid HTTP request such as OPTIONS. This occurs because the HTTP request handler enters a miscoded wbs_loop() debugger hook.
- Record
CVE-2021-27565- CVSS 3.1
- 7.5 High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - CVSS 2.0
- 5.0 Medium
AV:N/AC:L/Au:N/C:N/I:N/A:P - Weakness
- CWE-835
- Updated
- 2026-11-02
CVE List No score
The web server in InterNiche NicheStack through 4.0.1 allows remote attackers to cause a denial of service (infinite loop and networking outage) via an unexpected valid HTTP request such as OPTIONS. This occurs because the HTTP request handler enters a miscoded wbs_loop() debugger hook.
- Record
CVE-2021-27565- Updated
- 2026-11-02
EUVDEUVD-2021-14316 No score
The web server in InterNiche NicheStack through 4.0.1 allows remote attackers to cause a denial of service (infinite loop and networking outage) via an unexpected valid HTTP request such as OPTIONS. This occurs because the HTTP request handler enters a miscoded wbs_loop() debugger hook.
- Record
EUVD-2021-14316- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-r4v2-qg7m-3xrh No score
The web server in InterNiche NicheStack through 4.0.1 allows remote attackers to cause a denial...
The web server in InterNiche NicheStack through 4.0.1 allows remote attackers to cause a denial of service (infinite loop and networking outage) via an unexpected valid HTTP request such as OPTIONS. This occurs because the HTTP request handler enters a miscoded wbs_loop() debugger hook.
- Record
GHSA-r4v2-qg7m-3xrh- Weakness
- CWE-835
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2021-27565 is a high vulnerability (CVSS 7.5) in Hcc-embedded Nichestack, published August 19, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 2.59%, the 85th percentile. No source names a fixed version.