Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HSummary
CVE-2026-28389 is a high-severity NULL Pointer Dereference (CWE-476) vulnerability in Openssl Openssl. Its CVSS base score is 7.5 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Endpoint Denial of Service (T1499); ranked in the top 46% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to SA-11 (Developer Testing and Evaluation) and SA-15 (Development Process, Standards, and Tools) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-28389 is a NULL pointer dereference vulnerability in the OpenSSL cryptographic library. The issue arises during processing of a crafted CMS EnvelopedData message that uses KeyAgreeRecipientInfo, where the optional parameters field of the KeyEncryptionAlgorithmIdentifier is examined without first checking for its presence, resulting in a crash if the field is absent. Applications and services that invoke CMS_decrypt() on untrusted input, such as those involved in S/MIME processing or CMS-based protocols, are affected. OpenSSL FIPS modules in versions 3.6, 3.5, 3.4, 3.3, and 3.0 are not vulnerable, as the affected code lies outside the FIPS module boundary. The vulnerability has a CVSS v3.1 base score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H) and is associated with CWE-476.
A network-accessible attacker can exploit this vulnerability by supplying a maliciously crafted CMS EnvelopedData message to a vulnerable application. No privileges, authentication, or user interaction are required. Exploitation triggers a denial of service condition, causing the application to crash before any authentication or cryptographic operations can occur.
OpenSSL has addressed the vulnerability through fixes in their GitHub repository, including commits 16cea4188e0ea567deb4f93f85902247e67384f5, 785cbf7ea3b5a6f5adf0c1ccb92b79d89c35c616, 7b5274e812400cacb6f3be4c2df5340923fa807f, c6725634e089eb2b634b10ede33944be7248172a, and f80f83bc5fd036bc47d773e8b15a001e2b4ce686. Security practitioners should update to patched OpenSSL versions incorporating these changes.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-19965
Vulnerability Data
Issue summary: During processing of a crafted CMS EnvelopedData message with KeyAgreeRecipientInfo a NULL pointer dereference can happen. Impact summary: Applications that process attacker-controlled CMS data may crash before authentication or cryptographic operations occur resulting in Denial of Service. When…
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a CMS EnvelopedData message that uses KeyAgreeRecipientInfo is processed, the optional parameters field of KeyEncryptionAlgorithmIdentifier is examined without checking for its presence. This results in a NULL pointer dereference if the field is missing. Applications and services that call CMS_decrypt() on untrusted input (e.g., S/MIME processing or CMS-based protocols) are vulnerable. The FIPS modules in 3.6, 3.5, 3.4, 3.3 and 3.0 are not affected by this issue, as the affected code is outside the OpenSSL FIPS module boundary.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Developer testing and evaluation (including static analysis) directly finds null-dereference bugs before deployment.
Documented development standards and tools can enforce null-safety rules and safe pointer usage.
Engineering principles can mandate defensive coding such as explicit null checks before dereference.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure SDLC practices (static analysis, code review, safe coding standards) directly prevent NULL dereference bugs during development.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Security testing can detect NULL dereference defects before release.
Secure SDLC mandates defensive coding practices that can prevent NULL dereferences.
Application security requirements can specify input validation and pointer-safety rules.
Secure architecture principles encourage defensive design that avoids unsafe pointer use.
Secure coding standards directly require NULL-pointer checks and safe dereference patterns.