CVE-2021-38311

7.5 highEPSS 0.9%

High (7.5) in contiki-os contiki. EPSS 0.9% chance of exploitation in the next 30 days.

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.

Severity

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

EPSS: 0.9% chance of exploitation in the next 30 days; higher than 60% of CVEs (scores of 2026-10-31)
CWE: CWE-835
Published: 2021-08-09
Modified: 2026-06-17
Record from: the NVD, synced 2026-10-19

Affected

contiki-os:contiki

References

https://github.com/contiki-os/contiki/issues/2685
https://github.com/contiki-os/contiki/issues/2685

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