PatchTheCVECVE-2021-38386: In Contiki 3.0, a buffer overflow in the Telnet service allows remote attackers to cause a denial of service b
CVE-2021-38386 is a high-severity flaw (CVSS 7.5) affecting contiki. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
In Contiki 3.0, a buffer overflow in the Telnet service allows remote attackers to cause a denial of service because the ls command is mishandled when a directory has many files with long names.
Why this priority
- High severity
- Remotely exploitable, no login, no user action
No fix is published yet: follow the downgrade or mitigation steps.
Risk facts
| CVSS score | 7.5 (High) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 1.3% (top 30%) |
| CISA exploited list | No |
| Weakness | CWE-120 |
| Published | 2021-08-10 |
| Last modified | 2026-06-17 |
Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2021-38386?
contiki: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.
Is CVE-2021-38386 being exploited?
CVE-2021-38386 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2021-38386 affect?
CVE-2021-38386 affects contiki. Severity is high (CVSS 7.5). In Contiki 3.0, a buffer overflow in the Telnet service allows remote attackers to cause a denial of service because the ls command is mishandled when a directory has many files with long names.
How urgent is CVE-2021-38386?
Priority 49/100. High severity; Remotely exploitable, no login, no user action
Related CVEs
- CVE-2021-40523 HIGH 7.5 MITIGATE In Contiki 3.0, Telnet option negotiation is mishandled
- CVE-2021-38387 HIGH 7.5 MITIGATE In Contiki 3.0, a Telnet server that silently quits (before disconnection with clients) leads to connected cli
- CVE-2021-28362 HIGH 7.5 UPGRADE An issue was discovered in Contiki through 3.0
- CVE-2020-24336 CRITICAL 9.8 UPGRADE UPGRADE An issue was discovered in Contiki through 3.0 and Contiki-NG through 4.5
- CVE-2020-13986 HIGH 7.5 UPGRADE An issue was discovered in Contiki through 3.0