How severe is CVE-2009-2661?

CVE-2009-2661 has a CVSS 2.0 base score of 5.0, rated medium severity.

Is CVE-2009-2661 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (73rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2009-2661?

CVE-2009-2661 primarily affects Strongswan. In total, 24 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2009-2661?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2009-2661 published?

CVE-2009-2661 was published on 2009-08-04 and last updated on 2026-06-16.

CVE-2009-2661

CVE-2009-2661 is a medium-severity vulnerability in Strongswan with a CVSS 2.0 base score of 5.0. 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-310.

Key facts

Severity: Medium (CVSS 2.0 base score 5.0)
EPSS exploit prediction: 2% (73rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-310
Affected product: Strongswan
Published: 2009-08-04
Last modified: 2026-06-16

Description

The asn1_length function in strongSwan 2.8 before 2.8.11, 4.2 before 4.2.17, and 4.3 before 4.3.3 does not properly handle X.509 certificates with crafted Relative Distinguished Names (RDNs), which allows remote attackers to cause a denial of service (pluto IKE daemon crash) via malformed ASN.1 data. NOTE: this is due to an incomplete fix for CVE-2009-2185.

Frequently asked questions

What is CVE-2009-2661?: The asn1_length function in strongSwan 2.8 before 2.8.11, 4.2 before 4.2.17, and 4.3 before 4.3.3 does not properly handle X.509 certificates with crafted Relative Distinguished Names (RDNs), which allows remote attackers to cause a denial of service (pluto IKE daemon crash) via malformed ASN.1 data. NOTE: this is due to an incomplete fix for CVE-2009-2185.
How severe is CVE-2009-2661?: CVE-2009-2661 has a CVSS 2.0 base score of 5.0, rated medium severity.
Is CVE-2009-2661 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (73rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2009-2661?: CVE-2009-2661 primarily affects Strongswan. In total, 24 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2009-2661?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2009-2661 published?: CVE-2009-2661 was published on 2009-08-04 and last updated on 2026-06-16.

References

Affected products (24)

cpe:2.3:a:strongswan:strongswan:2.8.0:*:*:*:*:*:*:*
cpe:2.3:a:strongswan:strongswan:2.8.1:*:*:*:*:*:*:*
cpe:2.3:a:strongswan:strongswan:2.8.2:*:*:*:*:*:*:*
cpe:2.3:a:strongswan:strongswan:2.8.3:*:*:*:*:*:*:*
cpe:2.3:a:strongswan:strongswan:2.8.4:*:*:*:*:*:*:*
cpe:2.3:a:strongswan:strongswan:2.8.5:*:*:*:*:*:*:*
cpe:2.3:a:strongswan:strongswan:2.8.6:*:*:*:*:*:*:*
cpe:2.3:a:strongswan:strongswan:2.8.7:*:*:*:*:*:*:*
cpe:2.3:a:strongswan:strongswan:2.8.8:*:*:*:*:*:*:*
cpe:2.3:a:strongswan:strongswan:2.8.10:*:*:*:*:*:*:*
cpe:2.3:a:strongswan:strongswan:4.2.0:*:*:*:*:*:*:*
cpe:2.3:a:strongswan:strongswan:4.2.1:*:*:*:*:*:*:*
cpe:2.3:a:strongswan:strongswan:4.2.2:*:*:*:*:*:*:*
cpe:2.3:a:strongswan:strongswan:4.2.3:*:*:*:*:*:*:*
cpe:2.3:a:strongswan:strongswan:4.2.10:*:*:*:*:*:*:*
cpe:2.3:a:strongswan:strongswan:4.2.11:*:*:*:*:*:*:*
cpe:2.3:a:strongswan:strongswan:4.2.12:*:*:*:*:*:*:*
cpe:2.3:a:strongswan:strongswan:4.2.13:*:*:*:*:*:*:*
cpe:2.3:a:strongswan:strongswan:4.2.14:*:*:*:*:*:*:*
cpe:2.3:a:strongswan:strongswan:4.2.15:*:*:*:*:*:*:*
cpe:2.3:a:strongswan:strongswan:4.2.16:*:*:*:*:*:*:*
cpe:2.3:a:strongswan:strongswan:4.3.0:*:*:*:*:*:*:*
cpe:2.3:a:strongswan:strongswan:4.3.1:*:*:*:*:*:*:*
cpe:2.3:a:strongswan:strongswan:4.3.2:*:*:*:*:*:*:*

More vulnerabilities in Strongswan

CVE-2004-0590 — Critical (CVSS 10.0): FreeS/WAN 1.x and 2.x, and other related products including superfreeswan 1.x, openswan 1.x before 1.0.6, openswan 2.x…
CVE-2023-41913 — Critical (CVSS 9.8): strongSwan before 5.9.12 has a buffer overflow and possible unauthenticated remote code execution via a DH public value…
CVE-2023-26463 — Critical (CVSS 9.8): strongSwan 5.9.8 and 5.9.9 potentially allows remote code execution because it uses a variable named "public" for two…
CVE-2015-3991 — Critical (CVSS 9.8): strongSwan 5.2.2 and 5.3.0 allows remote attackers to cause a denial of service (daemon crash) or execute arbitrary…
CVE-2021-45079 — Critical (CVSS 9.1): In strongSwan before 5.9.5, a malicious responder can send an EAP-Success message too early without actually…
CVE-2022-4967 — High (CVSS 7.7): strongSwan versions 5.9.2 through 5.9.5 are affected by authorization bypass through improper validation of certificate…

All CVEs affecting Strongswan →

Other CWE-310 (Cryptographic Issues) vulnerabilities

CVE-2014-7878 — Critical (CVSS 10.0): The Application Lifecycle Service (ALS) in HP Helion Cloud Development Platform 1.0, when a virtual machine is derived…
CVE-2013-3712 — Critical (CVSS 10.0): SUSE Studio Onsite 1.3.x before 1.3.6 and SUSE Studio Extension for System z 1.3 uses "static" secret tokens, which has…
CVE-2013-6952 — Critical (CVSS 10.0): The Belkin WeMo Home Automation firmware before 3949 has a hardcoded GPG key, which makes it easier for remote…
CVE-2013-6838 — Critical (CVSS 10.0): An unspecified Enghouse Interactive Professional Services "addon product" in Enghouse Interactive IVR Pro (VIP2000)…
CVE-2013-0137 — Critical (CVSS 10.0): The default configuration of the Digital Alert Systems DASDEC EAS device before 2.0-2 and the Monroe Electronics R189…
CVE-2011-5123 — Critical (CVSS 10.0): The Antivirus component in Comodo Internet Security before 5.3.175888.1227 does not check whether X.509 certificates in…

Browse all CWE-310 (Cryptographic Issues) vulnerabilities →