CVE-2021-40523

HIGH
7.5
CVSS Score
Published: September 5, 2021 at 06:26 PM UTC
Updated: June 17, 2026 at 04:07 AM UTC
1 product affected across 1 vendorContiki

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Severity
HIGH7.5
Exploit prediction
EPSS 1.0%

Description

In Contiki 3.0, Telnet option negotiation is mishandled. During negotiation between a server and a client, the server may fail to give the WILL/WONT or DO/DONT response for DO and WILL commands because of improper handling of exception condition, which leads to property violations and denial of service. Specifically, a server sometimes sends no response, because a fixed buffer space is available for all responses and that space may have been exhausted.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

References (1)

x_refsource_MISCPatchThird Party Advisory
https://github.com/contiki-os/contiki/issues/2686

CVSS

Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
NONE
Availability
HIGH
Vector?

Quick Info

StatusMODIFIED
CWE
CWE-754

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