Mishandling of IPv6 NDP timeout (CVE-2021-3384)

Advisory ID CVE Number Date discovered Severity Advisory revision
STORM-2020-049 CVE-2021-3384 11/17/2020 low v5

Vulnerability details

Mishandling of the IPv6 NDP timeout could cause a temporary denial of service.

Impacted products

Stormshield Network Security low SNS is impacted


Version Date Description
v1  03/01/2021 Initial release
v2  03/03/2021 Fix typo in “Impacted Versions” and “Solution”
v3  03/08/2021 Fix typo in “Impacted Versions” and “Solution”
v4 04/06/2021 Update fix version
v5 05/27/2021 Update fix version


Stormshield Network Security

CVSS v3.1 Overall Score: 3.9      


Impacted version

This vulnerability could allow an attacker to trigger a protection related to ARP/NDP tables management, which would temporarily prevent the system to contact new hosts via IPv4 or IPv6.


  • SNS 2.0.0 to 2.7.7
  • SNS 2.8.0 to 2.16.0
  • SNS 3.0.0 to 3.7.17
  • SNS 3.8.0 to 3.11.5
  • SNS 4.0.0 to 4.1.4
  • SNS 4.2.1

Workaround solution


There is no workaround solution.

The vulnerability is fixed in versions:

  • 2.7.8
  • 3.7.18
  • 3.11.6
  • 4.1.5
  • 4.2.2

Attack Vector Attack Complexity Privileges Required User Interaction Scope Confidentiality Impact Integrity Impact Availability impact
Network Low None None Unchanged None None Low
CVSS Base score: 5.3 CVSS Vector: (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L)
Exploit Code Maturity Remediation Level Report Confidence
Unproven that exploit exists Official fix Reasonable
CVSS Temporal score: 4.4 CVSS Vector: (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:U/RL:O/RC:R)
Confidentiality Requirement Integrity Requirement Availability Requirement
Low Low Low
CVSS Environmental score: 3.9 CVSS Vector: (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:U/RL:O/RC:R/CR:L/IR:L/AR:L/MAV:X/MAC:X/MPR:X/MUI:X/MS:X/MC:X/MI:X/MA:X)


Stormshield thanks the R&D and especially @p_jalaber for discovering this issue.