SOC status:Duty analyst on shift

UK Cyber Defence
VulnerabilityModified

CVE-2021-28362

Because the packet length and the extension header length are unchecked (with respect to the available data) at this stage, and these variables are susceptible to integer underflow, it is possible to construct an invalid extension header that will cause…

HIGH 7.5EPSS 1.35%

Does this matter?

High impact if exploited, but EPSS currently rates exploitation as unlikely (1.35%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.

Description

An issue was discovered in Contiki through 3.0. When sending an ICMPv6 error message because of invalid extension header options in an incoming IPv6 packet, there is an attempt to remove the RPL extension headers. Because the packet length and the extension header length are unchecked (with respect to the available data) at this stage, and these variables are susceptible to integer underflow, it is possible to construct an invalid extension header that will cause memory corruption issues and lead to a Denial-of-Service condition. This is related to rpl-ext-header.c.

CVSS 3.1
7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS
1.35% probability · 71th percentile
Public exploits
None in Exploit-DB
CISA KEV
Not listed
Weakness
CWE-191
Affected
contiki-os/contiki
Source
cve@mitre.org
EPSS trend
0%3%5%26 October 2026: 1.35%26 October 202626 October 2026

EPSS 1.4% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.