Vulnerability Monitor

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CVE-2021-41991


The in-memory certificate cache in strongSwan before 5.9.4 has a remote integer overflow upon receiving many requests with different certificates to fill the cache and later trigger the replacement of cache entries. The code attempts to select a less-often-used cache entry by means of a random number generator, but this is not done correctly. Remote code execution might be a slight possibility.


Security Impact Summary

This vulnerability carries a HIGH severity rating with a CVSS v3.1 score of 7.5, indicating it can be exploited remotely over the network with relatively low complexity without requiring user interaction and does not require pre-existing privileges . The vulnerability impacts and availability (service disruption) for affected systems. Impacting 46 products from strongswan, from debian, from fedoraproject and 43 others, organizations running these solutions should prioritize assessment and patching.

Historical Context

Reported in 2021, this vulnerability emerged during an era marked by increased sophistication in supply chain attacks, cloud infrastructure vulnerabilities, and software-as-a-service (SaaS) security challenges. Security practices during this period emphasized zero-trust architectures, container security, and API protection.


Published

2021-10-18T14:15:10.333

Last Modified

2024-11-21T06:27:02.090

Status

Modified

Source

[email protected]

Severity

CVSSv3.1: 7.5 (HIGH)

CVSSv2 Vector

AV:N/AC:L/Au:N/C:N/I:N/A:P

  • Access Vector: NETWORK
  • Access Complexity: LOW
  • Authentication: NONE
  • Confidentiality Impact: NONE
  • Integrity Impact: NONE
  • Availability Impact: PARTIAL
Exploitability Score

10.0

Impact Score

2.9

Weaknesses
  • Type: Primary
    CWE-190

Affected Vendors & Products
Type Vendor Product Version/Range Vulnerable?
Application strongswan strongswan < 5.9.4 Yes
Operating System debian debian_linux 9.0 Yes
Operating System debian debian_linux 10.0 Yes
Operating System debian debian_linux 11.0 Yes
Operating System fedoraproject fedora 33 Yes
Operating System fedoraproject fedora 34 Yes
Operating System fedoraproject fedora 35 Yes
Application siemens sinema_remote_connect_server - Yes
Operating System siemens siplus_et_200sp_cp_1542sp-1_irc_tx_rail_firmware - Yes
Hardware siemens siplus_et_200sp_cp_1542sp-1_irc_tx_rail - No
Operating System siemens simatic_cp_1243-1_firmware - Yes
Hardware siemens simatic_cp_1243-1 - No
Operating System siemens simatic_cp_1242-7_gprs_v2_firmware - Yes
Hardware siemens simatic_cp_1242-7_gprs_v2 - No
Operating System siemens simatic_net_cp_1243-8_irc_firmware - Yes
Hardware siemens simatic_net_cp_1243-8_irc - No
Operating System siemens scalance_sc632-2c_firmware - Yes
Hardware siemens scalance_sc632-2c - No
Operating System siemens siplus_et_200sp_cp_1543sp-1_isec_firmware - Yes
Hardware siemens siplus_et_200sp_cp_1543sp-1_isec - No
Operating System siemens cp_1543-1_firmware - Yes
Hardware siemens cp_1543-1 - No
Operating System siemens simatic_net_cp_1545-1_firmware - Yes
Hardware siemens simatic_net_cp_1545-1 - No
Operating System siemens simatic_cp_1543sp-1_firmware - Yes
Hardware siemens simatic_cp_1543sp-1 - No
Operating System siemens simatic_net_cp1243-7_lte_eu_firmware - Yes
Hardware siemens simatic_net_cp1243-7_lte_eu - No
Operating System siemens simatic_cp_1243-7_lte\/us_firmware - Yes
Hardware siemens simatic_cp_1243-7_lte\/us - No
Operating System siemens simatic_cp_1542sp-1_firmware - Yes
Hardware siemens simatic_cp_1542sp-1 - No
Operating System siemens scalance_sc636-2c_firmware - Yes
Hardware siemens scalance_sc636-2c - No
Operating System siemens simatic_cp_1542sp-1_irc_firmware - Yes
Hardware siemens simatic_cp_1542sp-1_irc - No
Operating System siemens scalance_sc642-2c_firmware - Yes
Hardware siemens scalance_sc642-2c - No
Operating System siemens scalance_sc646-2c_firmware < 2.3 Yes
Hardware siemens scalance_sc646-2c - No
Operating System siemens scalance_sc622-2c_firmware - Yes
Hardware siemens scalance_sc622-2c - No
Operating System siemens siplus_s7-1200_cp_1243-1_rail_firmware - Yes
Hardware siemens siplus_s7-1200_cp_1243-1_rail - No
Operating System siemens siplus_s7-1200_cp_1243-1_firmware - Yes
Hardware siemens siplus_s7-1200_cp_1243-1 - No
Operating System siemens siplus_net_cp_1543-1_firmware - Yes
Hardware siemens siplus_net_cp_1543-1 - No
Operating System siemens siplus_et_200sp_cp_1543sp-1_isec_tx_rail_firmware - Yes
Hardware siemens siplus_et_200sp_cp_1543sp-1_isec_tx_rail - No

References

How SecUtils Interprets This CVE

SecUtils normalizes and enriches National Vulnerability Database (NVD) records by standardizing vendor and product identifiers, aggregating vulnerability metadata from both NVD and MITRE sources, and providing structured context for security teams. For strongswan's affected products, we extract Common Platform Enumeration (CPE) data, Common Weakness Enumeration (CWE) classifications, CVSS severity metrics, and reference data to enable rapid vulnerability prioritization and asset correlation. This record contains no exploit code, proof-of-concept instructions, or attack methodologies—only defensive intelligence necessary for patch management, risk assessment, and security operations.