Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2026-5443 is a critical-severity Out-of-bounds Write (CWE-787) vulnerability in Orthanc-Server Orthanc. Its CVSS base score is 9.8 (Critical).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 46th 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-2026-5443, published on 2026-04-09, is a heap buffer overflow vulnerability (CWE-787) that occurs during the decoding of PALETTE COLOR DICOM images. The flaw stems from pixel length validation that relies on 32-bit multiplication for width and height calculations; if these values overflow, the check erroneously passes, enabling the decoder to read from and write to memory beyond the allocated buffers. This affects DICOM processing components, as referenced in advisories for Orthanc server and related software.
The vulnerability carries a CVSS 3.1 base score of 9.8 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H), indicating critical severity with network accessibility, low complexity, and no privileges or user interaction required. Unauthenticated remote attackers can exploit it by supplying maliciously crafted PALETTE COLOR DICOM images, resulting in heap memory corruption that could lead to arbitrary code execution, sensitive data disclosure, or system crashes.
Mitigation guidance is available in vendor and advisory publications, including CERT's vulnerability note at https://kb.cert.org/vuls/id/536588, Machine Spirits at https://www.machinespirits.de/, and Orthanc server at https://www.orthanc-server.com/. Security practitioners should consult these for patching instructions, workarounds, and affected version details.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-20922
Vulnerability Data
A heap buffer overflow vulnerability exists during the decoding of `PALETTE COLOR` DICOM images. Pixel length validation uses 32-bit multiplication for width and height calculations. If these values overflow, the validation check incorrectly succeeds, allowing the decoder to read and…
more
write to memory beyond allocated buffers.
- 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 fuzzing and bounds checks) finds out-of-bounds write flaws before deployment.
Requiring documented secure-development standards and tools can mandate bounds-checked coding practices that avoid the weakness.
Input validation can structurally reject or sanitize data that would otherwise trigger an out-of-bounds write.
Memory-protection mechanisms limit the exploitability and blast radius of a successful out-of-bounds write.
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.
Vulnerability scanning and recording can discover out-of-bounds write flaws so they can be remediated.
Patching or replacing vulnerable software directly eliminates known instances of this coding weakness.
Secure-development practices (static analysis, bounds checking, code review) are the primary means of preventing out-of-bounds writes.
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.
Secure development life cycle mandates practices that prevent out-of-bounds writes.
Application security requirements can specify bounds-checking and safe memory handling.
Secure architecture and engineering principles reduce the likelihood of buffer overflows.
Secure coding directly addresses out-of-bounds writes through language choice and coding standards.
Security testing in development and acceptance can detect and prevent out-of-bounds write defects.
Change management can enforce review gates that catch unsafe memory operations before deployment.