CVE-2006-2940

CVE-2006-2940 is a high-severity vulnerability in Openssl with a CVSS 2.0 base score of 7.8. 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-399.

Key facts

• Severity: High (CVSS 2.0 base score 7.8)
• EPSS exploit prediction: 5% (91st percentile)
• Actively exploited: Not listed in CISA KEV
• Weakness: CWE-399
• Affected product: Openssl
• Published: 2006-09-28
• Last modified: 2026-06-16

Description

OpenSSL 0.9.7 before 0.9.7l, 0.9.8 before 0.9.8d, and earlier versions allows attackers to cause a denial of service (CPU consumption) via parasitic public keys with large (1) "public exponent" or (2) "public modulus" values in X.509 certificates that require extra time to process when using RSA signature verification.

Frequently asked questions

What is CVE-2006-2940?

OpenSSL 0.9.7 before 0.9.7l, 0.9.8 before 0.9.8d, and earlier versions allows attackers to cause a denial of service (CPU consumption) via parasitic public keys with large (1) "public exponent" or (2) "public modulus" values in X.509 certificates that require extra time to process when using RSA signature verification.

How severe is CVE-2006-2940?

CVE-2006-2940 has a CVSS 2.0 base score of 7.8, rated high severity.

Is CVE-2006-2940 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (91st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2006-2940?

CVE-2006-2940 primarily affects Openssl. In total, 47 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2006-2940?

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-2006-2940 published?

CVE-2006-2940 was published on 2006-09-28 and last updated on 2026-06-16.

References

• ftp://ftp.netbsd.org/pub/NetBSD/security/advisories/NetBSD-SA2008-007.txt.asc
• ftp://patches.sgi.com/support/free/security/advisories/20061001-01-P.asc
• http://docs.info.apple.com/article.html?artnum=304829
• http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?objectID=c01118771
• http://issues.rpath.com/browse/RPL-613
• http://itrc.hp.com/service/cki/docDisplay.do?docId=c00805100
• http://itrc.hp.com/service/cki/docDisplay.do?docId=c00849540
• http://kolab.org/security/kolab-vendor-notice-11.txt
• http://lists.apple.com/archives/security-announce/2006/Nov/msg00001.html
• http://lists.grok.org.uk/pipermail/full-disclosure/2006-September/049715.html
• http://lists.vmware.com/pipermail/security-announce/2008/000008.html
• http://marc.info/?l=bind-announce&m=116253119512445&w=2
• http://marc.info/?l=bugtraq&m=130497311408250&w=2
• http://openbsd.org/errata.html#openssl2
• http://openvpn.net/changelog.html
• http://secunia.com/advisories/22094
• http://secunia.com/advisories/22116
• http://secunia.com/advisories/22130
• http://secunia.com/advisories/22165
• http://secunia.com/advisories/22166
• http://secunia.com/advisories/22172
• http://secunia.com/advisories/22186
• http://secunia.com/advisories/22193
• http://secunia.com/advisories/22207
• http://secunia.com/advisories/22212
• http://secunia.com/advisories/22216
• http://secunia.com/advisories/22220
• http://secunia.com/advisories/22240
• http://secunia.com/advisories/22259
• http://secunia.com/advisories/22260

Affected products (47)

• cpe:2.3:a:openssl:openssl:0.9.1c:*:*:*:*:*:*:*
• cpe:2.3:a:openssl:openssl:0.9.2b:*:*:*:*:*:*:*
• cpe:2.3:a:openssl:openssl:0.9.3:*:*:*:*:*:*:*
• cpe:2.3:a:openssl:openssl:0.9.3a:*:*:*:*:*:*:*
• cpe:2.3:a:openssl:openssl:0.9.4:*:*:*:*:*:*:*
• cpe:2.3:a:openssl:openssl:0.9.5:*:*:*:*:*:*:*
• cpe:2.3:a:openssl:openssl:0.9.5:beta1:*:*:*:*:*:*
• cpe:2.3:a:openssl:openssl:0.9.5:beta2:*:*:*:*:*:*
• cpe:2.3:a:openssl:openssl:0.9.5a:*:*:*:*:*:*:*
• cpe:2.3:a:openssl:openssl:0.9.5a:beta1:*:*:*:*:*:*
• cpe:2.3:a:openssl:openssl:0.9.5a:beta2:*:*:*:*:*:*
• cpe:2.3:a:openssl:openssl:0.9.6:*:*:*:*:*:*:*
• cpe:2.3:a:openssl:openssl:0.9.6:beta1:*:*:*:*:*:*
• cpe:2.3:a:openssl:openssl:0.9.6:beta2:*:*:*:*:*:*
• cpe:2.3:a:openssl:openssl:0.9.6:beta3:*:*:*:*:*:*
• cpe:2.3:a:openssl:openssl:0.9.6a:*:*:*:*:*:*:*
• cpe:2.3:a:openssl:openssl:0.9.6a:beta1:*:*:*:*:*:*
• cpe:2.3:a:openssl:openssl:0.9.6a:beta2:*:*:*:*:*:*
• cpe:2.3:a:openssl:openssl:0.9.6a:beta3:*:*:*:*:*:*
• cpe:2.3:a:openssl:openssl:0.9.6b:*:*:*:*:*:*:*
• cpe:2.3:a:openssl:openssl:0.9.6c:*:*:*:*:*:*:*
• cpe:2.3:a:openssl:openssl:0.9.6d:*:*:*:*:*:*:*
• cpe:2.3:a:openssl:openssl:0.9.6e:*:*:*:*:*:*:*
• cpe:2.3:a:openssl:openssl:0.9.6f:*:*:*:*:*:*:*
• cpe:2.3:a:openssl:openssl:0.9.6g:*:*:*:*:*:*:*
• cpe:2.3:a:openssl:openssl:0.9.6h:*:*:*:*:*:*:*
• cpe:2.3:a:openssl:openssl:0.9.6i:*:*:*:*:*:*:*
• cpe:2.3:a:openssl:openssl:0.9.6j:*:*:*:*:*:*:*
• cpe:2.3:a:openssl:openssl:0.9.6k:*:*:*:*:*:*:*
• cpe:2.3:a:openssl:openssl:0.9.6l:*:*:*:*:*:*:*
• cpe:2.3:a:openssl:openssl:0.9.6m:*:*:*:*:*:*:*
• cpe:2.3:a:openssl:openssl:0.9.7:*:*:*:*:*:*:*
• cpe:2.3:a:openssl:openssl:0.9.7a:*:*:*:*:*:*:*
• cpe:2.3:a:openssl:openssl:0.9.7b:*:*:*:*:*:*:*
• cpe:2.3:a:openssl:openssl:0.9.7c:*:*:*:*:*:*:*
• cpe:2.3:a:openssl:openssl:0.9.7d:*:*:*:*:*:*:*
• cpe:2.3:a:openssl:openssl:0.9.7e:*:*:*:*:*:*:*
• cpe:2.3:a:openssl:openssl:0.9.7f:*:*:*:*:*:*:*
• cpe:2.3:a:openssl:openssl:0.9.7g:*:*:*:*:*:*:*
• cpe:2.3:a:openssl:openssl:0.9.7h:*:*:*:*:*:*:*

More vulnerabilities in Openssl

• CVE-2009-3245 — Critical (CVSS 10.0): OpenSSL before 0.9.8m does not check for a NULL return value from bn_wexpand function calls in (1) crypto/bn/bn_div.c,…
• CVE-2006-3738 — Critical (CVSS 10.0): Buffer overflow in the SSL_get_shared_ciphers function in OpenSSL 0.9.7 before 0.9.7l, 0.9.8 before 0.9.8d, and earlier…
• CVE-2026-31789 — Critical (CVSS 9.8): Issue summary: Converting an excessively large OCTET STRING value to a hexadecimal string leads to a heap buffer…
• CVE-2022-2274 — Critical (CVSS 9.8): The OpenSSL 3.0.4 release introduced a serious bug in the RSA implementation for X86_64 CPUs supporting the AVX512IFMA…
• CVE-2021-3711 — Critical (CVSS 9.8): In order to decrypt SM2 encrypted data an application is expected to call the API function EVP_PKEY_decrypt().…
• CVE-2016-6309 — Critical (CVSS 9.8): statem/statem.c in OpenSSL 1.1.0a does not consider memory-block movement after a realloc call, which allows remote…

All CVEs affecting Openssl →

Other CWE-399 (Resource Management Errors) vulnerabilities

• CVE-2015-8104 — Critical (CVSS 10.0): The KVM subsystem in the Linux kernel through 4.2.6, and Xen 4.3.x through 4.6.x, allows guest OS users to cause a…
• CVE-2015-0339 — Critical (CVSS 10.0): Adobe Flash Player before 13.0.0.277 and 14.x through 17.x before 17.0.0.134 on Windows and OS X and before…
• CVE-2015-0335 — Critical (CVSS 10.0): Adobe Flash Player before 13.0.0.277 and 14.x through 17.x before 17.0.0.134 on Windows and OS X and before…
• CVE-2015-0333 — Critical (CVSS 10.0): Adobe Flash Player before 13.0.0.277 and 14.x through 17.x before 17.0.0.134 on Windows and OS X and before…
• CVE-2014-4121 — Critical (CVSS 10.0): Microsoft .NET Framework 2.0 SP2, 3.5, 3.5.1, 4, 4.5, 4.5.1, and 4.5.2 does not properly parse internationalized…
• CVE-2014-0560 — Critical (CVSS 10.0): Use-after-free vulnerability in Adobe Reader and Acrobat 10.x before 10.1.12 and 11.x before 11.0.09 on Windows and OS…

Browse all CWE-399 (Resource Management Errors) vulnerabilities →

Threat intelligence

Threat-intel indicators referencing this CVE:

• 90.160.135.217 (ipv4-addr)
• 62.36.19.42 (ipv4-addr)
• 62.36.19.41 (ipv4-addr)