01 Record
CVE-2021-40523
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
UnratedPUBLISHEDCNA: mitre
CNA base scoreUnratedNo CNA CVSS vector
02 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
03 Exploitation and scoring
- Exploitation
- Not assessed. CISA has not published an exploitation assessment for this record, and it is not in the KEV catalog. That is an absence of assessment, not a finding of no risk.
- SSVC decision
- Not assessed by CISA
- EPSS probability
- 0.96% probability of exploitation activity in the next 30 days.
- EPSS percentile
- Equal to or higher than the score of 61.1% of scored records. A rank, not a probability.
- NVD base score
- 7.5 (CVSS v3.x), scored by the NVD independently of the CNA.
- NVD CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- NVD analysis status
- Modified. NVD last modified this record on 2026-06-17.
- Red Hat severity
- No Red Hat rating. Red Hat rates the CVEs that affect its products.
Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.
04 Metadata
- Published
- 2021-09-05 18:26Z5 YR AGO
- Last updated
- 2024-08-04 02:44Z2 YR AGO
- Reserved
- 2021-09-05
- Assigning CNA
- mitre
- Record state
- PUBLISHED
- Severity
- Not rated by the issuing CNA
- CNA CVSS vector
- Not published by the issuing CNA
- Weaknesses
- CWE-754Improper Check for Unusual or Exceptional ConditionsClass
- Data version
- 5.1
- Document digest
- dc038bfda1c1a9e49990f9b9ee44f81bc257ab6eaf4f3a3e365e37292e4cae8f
05 Affected products
VendorProductVersionsPlatforms