CVE-2020-27634
In Contiki 4.5, TCP ISNs are improperly random.
9.1 Critical
In Contiki 4.5, TCP ISNs are improperly random.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- None
Exploit likelihood
1.72%Up 1.7 points since Oct 11, 2023
What each source reports
NVD Score used
In Contiki 4.5, TCP ISNs are improperly random.
- Record
CVE-2020-27634- CVSS 3.1
- 9.1 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N - Weakness
- CWE-330
- Updated
- 2026-11-02
CVE List No score
In Contiki 4.5, TCP ISNs are improperly random.
- Record
CVE-2020-27634- Updated
- 2026-11-02
EUVDEUVD-2020-20141 No score
In Contiki 4.5, TCP ISNs are improperly random.
- Record
EUVD-2020-20141- Updated
- 2026-11-03
GitHub AdvisoriesGHSA-pw9j-jvfg-9ppw
In Contiki 4.5, TCP ISNs are improperly random.
In Contiki 4.5, TCP ISNs are improperly random.
- Record
GHSA-pw9j-jvfg-9ppw- CVSS 3.1
- 9.1 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N - Weakness
- CWE-330
- Updated
- 2026-11-02
Affected products
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2020-27634 is a critical vulnerability (CVSS 9.1) in Contiki-ng, published October 10, 2023. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.72%, the 77th percentile. No source names a fixed version.