CVE-2026-42766 Details
Issue summary: A specially crafted password-encrypted CMS message
can trigger a NULL pointer dereference during CMS decryption.

Impact summary: This NULL pointer dereference leads to an application crash
and a Denial of Service.

The CMS PasswordRecipientInfo.keyDerivationAlgorithm field is defined as
OPTIONAL in the ASN.1 specification and may therefore be absent in specially
crafted inputs. During the password-based CMS decryption the OpenSSL
CMS implementation dereferences this field without first checking whether it
was present.

An attacker who supplies such a CMS message to an application performing
password-based CMS decryption can trigger an application crash, leading to
a Denial of Service.

Applications that process password-encrypted CMS messages may be affected.

The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this
issue, as the affected code is outside the OpenSSL FIPS module boundary.
View at NVD
Exploit prediction scoring system (EPSS) score for CVE-2026-42766
EPSS (Exploit Prediction Scoring System): EPSS predicts the likelihood that a vulnerability will be exploited in the wild. A higher percentage means a greater chance of an exploit occurring. The EPSS model produces a probability score between 0 and 1 (0 and 100%).
0.6 Probability of exploitation activity being observed over the next 30 days (44th percentile)
CVSS score for CVE-2026-42766
CVSS (Common Vulnerability Scoring System): An open framework owned and managed by FIRST.Org, Inc. that assigns a numerical score from 0 to 10 to software vulnerabilities to indicate their severity.
5.9 Medium
Products affected by CVE-2026-42766
OpenSSL 1.1.1o
OpenSSL 1.1.1p
OpenSSL 1.1.1q
OpenSSL 1.1.1s
OpenSSL 1.1.1t
DVE Score by Bitsight AI
DVE scores complement traditional static scoring systems like CVSS with Bitsight AI powered real-time threat intelligence and underground cyber criminal activity so that security teams can reduce alert fatigue and focus on vulnerabilities most likely to be exploited.
Low
More on DVE scores

CVE-2026-42766 Global Footprint

Top 10 Identified Countries

Country Observations Percentage
US 25,468 28.00%
JP 10,288 11.31%
DE 5,831 6.41%
NL 3,462 3.81%
IN 3,172 3.49%
CA 3,105 3.41%
KR 3,024 3.32%
FR 2,935 3.23%
CN 2,914 3.20%
GB 2,506 2.75%

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CVE-2026-42766 Industry Footprint

Top 10 Identified Industries

*Service provider organizations (typically Technology and Telecommunications) are disproportionally represented in the results given their upstream ownership of end-user infrastructure. See our FAQs.

Industry* Observations Percentage
Technology 47,167 75.22%
Telecommunications 10,460 16.68%
Education 2,456 3.92%
Government/Politics 739 1.18%
Business Services 302 0.48%
Manufacturing 204 0.33%
Finance 159 0.25%
Healthcare/Wellness 154 0.25%
Media/Entertainment 131 0.21%
Food Production 128 0.20%

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