In Contiki 3.0, potential nonterminating acknowledgment loops exist in the Telnet service.
Priority LOW 35CWE-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
- No fix listed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-835.
Summary
In Contiki 3.0, potential nonterminating acknowledgment loops exist in the Telnet service. When the negotiated options are already disabled, servers still respond to DONT and WONT requests with WONT or DONT commands, which may lead to infinite acknowledgment loops, denial of service, and excessive CPU consumption.
Why it matters now
EPSS 0.00942 61st percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix No fix listed No fixed version in the sources yet
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 |
- — Vendor— Affected all versions Fixed in — No fix listed CNA
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:contiki-os:contiki:3.0:*:*:*:*:*:*:* | 3.0 | Vulnerable | Contiki-os |
- cpe:2.3:o:contiki-os:contiki:3.0:*:*:*:*:*:*:* Versions 3.0 Vulnerable ·Contiki-os
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2021-38311
- 2026-10-03 Alias added: GHSA-cw9g-qwf2-42hw
References
More Contiki-os Contiki vulnerabilities
- TI-2020-14885 An issue was discovered in Contiki through 3.0 and Contiki-NG through 4.5. CVSS 3.1CRITICAL 9.8
- TI-2019-06001 An issue was discovered in Contiki-NG through 4.3 and Contiki through 3.0. CVSS 3.1CRITICAL 9.8
- TI-2020-10954 An issue was discovered in Contiki through 3.0. CVSS 3.1HIGH 7.5
- TI-2020-10955 An issue was discovered in Contiki through 3.0. CVSS 3.1HIGH 7.5
- TI-2019-06643 An issue was discovered in Contiki-NG through 4.3 and Contiki through 3.0. CVSS 3.1HIGH 7.5
- TI-2021-09524 An issue was discovered in Contiki through 3.0. CVSS 3.1HIGH 7.5
Sources
- CVE-2021-38311 · CVE Program
- CVE-2021-38311 · NVD
- FIRST EPSS
- GHSA-cw9g-qwf2-42hw · GitHub Advisory Database · CC BY 4.0
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