Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HSummary
CVE-2026-34874 is a high-severity NULL Pointer Dereference (CWE-476) vulnerability in Trustedfirmware Mbed Tls. Its CVSS base score is 7.5 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Endpoint Denial of Service (T1499); ranked at the 20th percentile by exploit likelihood (below the median); 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-2026-34874 is a NULL pointer dereference vulnerability in Mbed TLS versions through 3.6.5 and 4.x through 4.0.0. The flaw occurs during distinguished name parsing, enabling an attacker to trigger a write to address 0. It carries 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 maps to CWE-476 (NULL Pointer Dereference). The vulnerability was published on 2026-04-01T19:16:33.390.
A remote, unauthenticated attacker can exploit this over the network with low attack complexity and no user interaction. Exploitation results in high availability impact with no confidentiality or integrity effects, typically manifesting as a denial-of-service via process crash in applications using the affected Mbed TLS library for X.509 parsing.
The Mbed TLS security advisories provide mitigation guidance, available at https://mbed-tls.readthedocs.io/en/latest/security-advisories/ and specifically at https://mbed-tls.readthedocs.io/en/latest/security-advisories/mbedtls-security-advisory-2026-03-null-pointer-dereference-x509/.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-18003
Vulnerability Data
An issue was discovered in Mbed TLS through 3.6.5 and 4.x through 4.0.0. There is a NULL pointer dereference in distinguished name parsing that allows an attacker to write to address 0.
- 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.