CVE-2020-13986: An issue was discovered in Contiki through 3.0

Q: How do I fix CVE-2020-13986?

contiki: upgrade to newer than 3.0. Exact commands for each OS are on this page.

Q: Is CVE-2020-13986 being exploited?

CVE-2020-13986 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2020-13986 affect?

CVE-2020-13986 affects contiki. Severity is high (CVSS 7.5). An issue was discovered in Contiki through 3.0. An infinite loop exists in the uIP TCP/IP stack component when handling RPL extension headers of IPv6 network packets in rpl_remove_header in net/rpl/rpl-ext-header.c.

Q: How urgent is CVE-2020-13986?

Priority 53/100. High severity; Remotely exploitable, no login, no user action

This month

HIGH 7.5REMOTEUPGRADE

CVE-2020-13986 is a high-severity flaw (CVSS 7.5) affecting contiki. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An issue was discovered in Contiki through 3.0. An infinite loop exists in the uIP TCP/IP stack component when handling RPL extension headers of IPv6 network packets in rpl_remove_header in net/rpl/rpl-ext-header.c.

Why this priority

High severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	3.1% (top 12%)
CISA exploited list	No
Weakness	CWE-835
Published	2020-12-11
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: contiki-os

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2020-12-11 22:15 UTCPublished CVE record published
2026-06-17 02:54 UTCUpdated Record last modified

contiki-os contiki UPGRADE

Affected: <= 3.0

Fixed in: newer than 3.0

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2020-13986?

contiki: upgrade to newer than 3.0. Exact commands for each OS are on this page.

Is CVE-2020-13986 being exploited?

CVE-2020-13986 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2020-13986 affect?

CVE-2020-13986 affects contiki. Severity is high (CVSS 7.5). An issue was discovered in Contiki through 3.0. An infinite loop exists in the uIP TCP/IP stack component when handling RPL extension headers of IPv6 network packets in rpl_remove_header in net/rpl/rpl-ext-header.c.

How urgent is CVE-2020-13986?

Priority 53/100. High severity; Remotely exploitable, no login, no user action

Related CVEs

CVE-2021-40523 HIGH 7.5 MITIGATE In Contiki 3.0, Telnet option negotiation is mishandled
CVE-2021-38387 HIGH 7.5 MITIGATE In Contiki 3.0, a Telnet server that silently quits (before disconnection with clients) leads to connected cli
CVE-2021-38386 HIGH 7.5 MITIGATE In Contiki 3.0, a buffer overflow in the Telnet service allows remote attackers to cause a denial of service b
CVE-2021-28362 HIGH 7.5 UPGRADE An issue was discovered in Contiki through 3.0
CVE-2020-24336 CRITICAL 9.8 UPGRADE UPGRADE An issue was discovered in Contiki through 3.0 and Contiki-NG through 4.5

References

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