How severe is CVE-2021-41990?

CVE-2021-41990 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2021-41990 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 6% (93rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-41990?

CVE-2021-41990 primarily affects Strongswan. In total, 23 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2021-41990?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2021-41990 published?

CVE-2021-41990 was published on 2021-10-18 and last updated on 2026-06-17.

CVE-2021-41990

CVE-2021-41990 is a high-severity vulnerability in Strongswan with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-190.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 6% (93rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-190
Affected product: Strongswan
Published: 2021-10-18
Last modified: 2026-06-17

Description

The gmp plugin in strongSwan before 5.9.4 has a remote integer overflow via a crafted certificate with an RSASSA-PSS signature. For example, this can be triggered by an unrelated self-signed CA certificate sent by an initiator. Remote code execution cannot occur.

Frequently asked questions

What is CVE-2021-41990?: The gmp plugin in strongSwan before 5.9.4 has a remote integer overflow via a crafted certificate with an RSASSA-PSS signature. For example, this can be triggered by an unrelated self-signed CA certificate sent by an initiator. Remote code execution cannot occur.
How severe is CVE-2021-41990?: CVE-2021-41990 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2021-41990 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 6% (93rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-41990?: CVE-2021-41990 primarily affects Strongswan. In total, 23 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2021-41990?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2021-41990 published?: CVE-2021-41990 was published on 2021-10-18 and last updated on 2026-06-17.

References

Affected products (23)

cpe:2.3:a:strongswan:strongswan:*:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*
cpe:2.3:o:siemens:6gk6108-4am00-2ba2_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:siemens:6gk6108-4am00-2da2_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:siemens:6gk5804-0ap00-2aa2_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:siemens:6gk5812-1aa00-2aa2_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:siemens:6gk5812-1ba00-2aa2_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:siemens:6gk5816-1aa00-2aa2_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:siemens:6gk5816-1ba00-2aa2_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:siemens:6gk5826-2ab00-2ab2_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:siemens:6gk5874-2aa00-2aa2_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:siemens:6gk5874-3aa00-2aa2_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:siemens:6gk5876-3aa02-2ba2_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:siemens:6gk5876-3aa02-2ea2_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:siemens:6gk5876-4aa00-2ba2_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:siemens:6gk5876-4aa00-2da2_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:siemens:6gk5856-2ea00-3da1_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:siemens:6gk5856-2ea00-3aa1_firmware:-:*:*:*:*:*:*:*
cpe:2.3:o:siemens:6gk5615-0aa00-2aa2_firmware:-:*:*:*:*:*:*:*

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