Strongswan : Integer Overflow When Replacing Certificates in Cache

Advisory ID CVE Number Date discovered Severity Advisory revision
STORM-2021-065 cve-2021-41991 11/17/2021 medium v1

Vulnerability details

A vulnerability in stronsgwan can lead to a DoS of the IPSec functionality or unlikely to a RCE.

Impacted products

Stormshield Network Security medium SNS is impacted


Version Date Description
v1 12/08/2021 Initial release


Stormshield Network Security

CVSS v3.1 Overall Score: 6.5      


Impacted version

An attacker who makes several requests to connect to an IPSec tunnel with a valid certificate by modifying the signatureAlgorithm field will request the cache to store the different variants of the same certificate. As the cache management is poorly managed, a bad index calculation can lead to access to unauthorized memory, therefore a SEGFAULT or very improbably an RCE although an attacker does not have direct control over the dereferenced memory.

  • SNS 2.1.0 to 2.7.8
  • SNS 3.0.0 to 3.7.22
  • SNS 3.8.0 to 3.11.10
  • SNS 4.0.0 to 4.2.6

Workaround solution


There is no workaround solution.

The vulnerability is fixed in versions:

  • 2.7.9
  • 3.7.23
  • 3.11.11
  • 4.2.7

Attack Vector Attack Complexity Privileges Required User Interaction Scope Confidentiality Impact Integrity Impact Availability impact
Network High Low None Unchanged High High High
CVSS Base score: 7.5 CVSS Vector: (AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H)
Exploit Code Maturity Remediation Level Report Confidence
Unproven that exploit exists Official fix Confirmed
CVSS Temporal score: 6.5 CVSS Vector: (AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C)
Confidentiality Requirement Integrity Requirement Availability Requirement
High High High
CVSS Environmental score: 6.5 CVSS Vector: (AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C/CR:H/IR:H/AR:H/MAV:X/MAC:X/MPR:X/MUI:X/MS:X/MC:X/MI:X/MA:X)