Raw vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:HSummary
CVE-2026-27853 is a medium-severity Out-of-bounds Write (CWE-787) vulnerability in Powerdns Dnsdist. Its CVSS base score is 5.9 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 40th 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-2026-27853 is an out-of-bounds write vulnerability (CWE-787) in DNSdist, a DNS load balancer. It affects instances of DNSdist that use custom Lua code invoking the DNSQuestion:changeName or DNSResponse:changeName methods. An attacker can trigger this issue by sending crafted DNS responses, which may cause the rewritten packet to exceed its initial size and surpass 65535 bytes, rated at CVSS 5.9 (AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H). The vulnerability was published on 2026-03-31.
A remote attacker without privileges can exploit this over the network by crafting DNS responses targeted at a vulnerable DNSdist instance running the specified Lua methods. Exploitation requires high attack complexity, such as precisely manipulating response data to trigger the out-of-bounds write during name changes. Successful exploitation leads to a crash of the DNSdist process, resulting in denial of service with no impact on confidentiality or integrity.
The PowerDNS security advisory provides details on mitigation; see https://www.dnsdist.org/security-advisories/powerdns-advisory-for-dnsdist-2026-02.html for patches and recommended actions.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-17407
Vulnerability Data
An attacker might be able to trigger an out-of-bounds write by sending crafted DNS responses to a DNSdist using the DNSQuestion:changeName or DNSResponse:changeName methods in custom Lua code. In some cases the rewritten packet might become larger than the initial…
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response and even exceed 65535 bytes, potentially leading to a crash resulting in denial of service.
- 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.
Secure-development practices (static analysis, bounds checking, code review) are the primary means of preventing out-of-bounds writes.
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.
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 in development and acceptance can detect and prevent out-of-bounds write defects.
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.
Change management can enforce review gates that catch unsafe memory operations before deployment.