In Contiki 4.5, TCP ISNs are improperly random.
Priority MEDIUM 51CWE-330Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · None
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · NVD. Fix status from CNA.
Summary
In Contiki 4.5, TCP ISNs are improperly random.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.01716 77th percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | — | all versions | — | No fix listed | CNA |
- — Vendor— Affected all versions Fixed in — No fix listed CNA
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:o:contiki-ng:contiki-ng:4.5:*:*:*:*:*:*:* | 4.5 | Vulnerable | contiki-ng |
- cpe:2.3:o:contiki-ng:contiki-ng:4.5:*:*:*:*:*:*:* Versions 4.5 Vulnerable ·contiki-ng
Remediation
No fixed version listed by the sources yet.
Timeline
- 2026-10-02 Threatist record created from CVE-2020-27634
- 2026-10-03 Alias added: GHSA-pw9j-jvfg-9ppw
References
More Contiki-ng vulnerabilities
- TI-2020-14885 An issue was discovered in Contiki through 3.0 and Contiki-NG through 4.5. CVSS 3.1CRITICAL 9.8
- TI-2018-16029 contiki-ng version 4 contains a Buffer Overflow vulnerability in AQL (Antelope Query… CVSS 3.1CRITICAL 9.8
- TI-2018-13749 An issue was discovered in the MQTT server in Contiki-NG before 4.2. CVSS 3.0CRITICAL 10.0
- TI-2023-14381 Contiki-NG has off-by-one error in Antelope DBMS CVSS 3.1CRITICAL 9.8
- TI-2023-14839 Contiki-NG missing NULL pointer check in IPv6 neighbor discovery CVSS 3.1CRITICAL 9.8
- TI-2022-16354 Unverified DIO prefix info lengths in RPL-Classic in Contiki-NG CVSS 3.1CRITICAL 9.8
Sources
- CVE-2020-27634 · CVE Program
- CVE-2020-27634 · NVD
- FIRST EPSS
- GHSA-pw9j-jvfg-9ppw · GitHub Advisory Database · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences